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Printable geometry worksheet for calculating angles using clues, suitable for educational practice.

Worksheet titled "Calculating Angles (B) With Clues" featuring various geometric diagrams with missing angles to solve, including triangles, quadrilaterals, and intersecting lines, with instructions to find the missing angles using clues provided.

Worksheet titled "Calculating Angles (B) With Clues" featuring various geometric diagrams with missing angles to solve, including triangles, quadrilaterals, and intersecting lines, with instructions to find the missing angles using clues provided.

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Show Answer Key & Explanations Step-by-step solution for: Classifying angles worksheets | Worsheets library
Here are the step-by-step solutions to find the missing angles.

1. Top Left (Triangle with exterior angle)
* Angle $a^\circ$: Angles on a straight line add up to $180^\circ$. So, $a = 180 - 45 = 135$.
* Angle $b^\circ$: The sum of angles in a triangle is $180^\circ$. We have $90^\circ$ and $45^\circ$. So, $b = 180 - 90 - 45 = 45$.
* Angle $c^\circ$: This is an exterior angle. It equals the sum of the two opposite interior angles ($90 + 45$). Or, it is supplementary to angle $b$ ($180 - 45$). So, $c = 135$.

2. Top Right (Pentagon)
* Angles $f^\circ, i^\circ, k^\circ$: First, find the total sum of angles for a 5-sided shape (pentagon): $(5-2) \times 180 = 540^\circ$.
The known angles are $110^\circ$, $110^\circ$, and $130^\circ$. Their sum is $350^\circ$.
The remaining sum for $f, i, k$ is $540 - 350 = 190^\circ$.
Looking at the markings, angles $f$ and $k$ have single ticks (equal), and angle $i$ has a double tick (different). However, usually in these problems, unless specified, we look for symmetry or standard values. Let's look closer. Actually, looking at the diagram, $f$ and $k$ look like right angles ($90^\circ$) but aren't marked as such. Let's re-examine. Wait, there are no other clues. Let's look at the other shapes first to see if there's a pattern.
*Correction*: Let's look at the quadrilateral below it first, maybe it helps? No. Let's look at the pentagon again. If $f=k$, then $2f + i = 190$. Without more info, this is tricky. Let's look really closely at the image. Ah, angle $i$ looks like a reflex angle? No, it's inside. Let's assume standard integer values often found in these worksheets. If $f=90$ and $k=90$, then $i = 190 - 180 = 10$. That seems too small visually.
Let's re-read the pentagon. It has vertices. Let's look at the quadrilateral next to it.

3. Middle Left (Isosceles Triangle with parallel lines)
* Angle $d^\circ$: Alternate interior angles are equal. The bottom left angle is part of a transversal. Wait, the arrow indicates parallel vertical lines. The transversal cuts them. The angle labeled $70^\circ$ is alternate interior to angle $d$. So, $d = 70$.
* Angle $e^\circ$: This is an isosceles triangle (indicated by the tick marks on the sides). The base angles are equal. So the other base angle is also $70^\circ$. The top angle $e = 180 - 70 - 70 = 40$.
* Angle $g^\circ$: Corresponding angles or consecutive interior? Let's use the triangle sum again or parallel lines. Angle $g$ and the $70^\circ$ angle are consecutive interior angles if we consider the horizontal base? No. Let's use the fact that angles on a straight line at the bottom vertex sum to 180. We don't have enough info there.
Let's look at angle $g$ relative to the parallel lines. Angle $g$ and angle $d$ ($70^\circ$) are consecutive interior angles? No.
Let's look at the "Z" shape. The angle alternate to $d$ is $70$. The angle vertically opposite to the bottom-left corner of the triangle is... wait.
Let's restart this one carefully.
Vertical lines are parallel.
Transversal line creates angle $d$ and angle $70^\circ$. They are alternate interior angles. So $d = 70$.
The triangle is isosceles (ticks on legs). So the base angles are equal. Bottom-left is $70$, so bottom-right is $70$.
Top angle $e = 180 - 70 - 70 = 40$.
Angle $g$: Look at the intersection at the bottom right. The angle inside the triangle is $70$. Angle $g$ is vertically opposite to the angle adjacent to the parallel line? No.
Let's look at angle $g$ and the parallel line. Angle $g$ and the interior angle $70$ are consecutive interior angles (same side interior)? No, they are on opposite sides of the transversal.
Actually, angle $g$ corresponds to the angle supplementary to $d$?
Let's use the property that corresponding angles are equal. The angle corresponding to $d$ ($70$) is the angle above the parallel line. Angle $g$ is vertically opposite to the interior angle of the triangle? No.
Let's look at the position of $g$. It is outside the triangle. It forms a linear pair with the interior angle $70$? No, it's not on the straight line of the base. It's on the transversal.
Angle $g$ and the interior angle $70^\circ$ are vertically opposite? No.
Angle $g$ is corresponding to the angle $d$? No.
Let's look at the "F" shape. The angle corresponding to $d$ ($70$) is the angle at the bottom right, above the parallel line. Angle $g$ is vertically opposite to the interior angle ($70$)? If the line goes straight through, yes. But the diagram shows the triangle sitting on a vertex.
Actually, simpler view: Angle $g$ and the interior angle $70^\circ$ are alternate exterior angles? No.
Let's assume the line forming the right side of the triangle is a straight transversal. Then angle $g$ and the interior angle $70^\circ$ are supplementary (add to 180) because they form a linear pair on the transversal? No, they are on the same side of the parallel line?
Let's look at angle $h$. Angle $h$ and angle $g$ are vertically opposite? No.
Let's try this: Angle $g$ is an exterior angle to the parallel lines?
Okay, let's look at the relationship between $g$ and $d$. They are consecutive interior angles if we extend the lines? No.
Let's look at the Z-angle again. The angle alternate to $d$ is the interior angle $70$.
Angle $g$ is vertically opposite to the angle that is supplementary to $70$?
Let's look at the diagram again. $g$ is obtuse. $d$ is acute.
Angle $g$ and angle $d$ are consecutive interior angles on the same side of the transversal? If so, $g + d = 180$. $g = 110$.
Let's check $h$. $h$ and $g$ are on a straight line? No. $h$ is vertically opposite to the interior angle $70$? If the line is straight, yes. So $h = 70$? Or is $h$ corresponding to $d$? If $h$ corresponds to $d$, $h=70$.
Let's assume standard parallel line rules:
$d = 70$ (Alternate Interior).
$e = 40$ (Triangle Sum).
$g = 110$ (Consecutive Interior / Same-Side Interior with $d$? No, $g$ is at the other intersection. $g$ and the interior angle $70$ are consecutive interior? No. $g$ and $d$ are exterior consecutive? No.
Let's use Corresponding Angles. The angle corresponding to $d$ ($70$) is the angle in the same position at the bottom intersection (inside the triangle? No, above the parallel line). Let's call the angle above the bottom parallel line $x$. $x = 70$. Angle $g$ and $x$ are supplementary? No, they are vertically opposite? No.
Angle $g$ is vertically opposite to the interior angle $70$? If the side of the triangle is a straight line segment, then no.
Let's look at angle $h$. $h$ is vertically opposite to the interior angle $70$? No, $h$ is adjacent.
Actually, looking at the crossing lines:
Angle $g$ and the interior angle $70$ form a linear pair on the transversal? Yes, if the horizontal line is the parallel one. The transversal is the slanted line. The interior angle is between the parallels. Angle $g$ is outside. They are on the same side of the transversal. They are supplementary. So $g = 180 - 70 = 110$.
Angle $h$: Vertically opposite to angle $g$? No. Angle $h$ and angle $d$ are corresponding? Yes. So $h = 70$.
Angle $f$ (from the previous problem, wait, this is $g, h, f$? No, the labels are $d, e, g, h, f$? No, the labels are $d, e$ for the triangle, $g, h$ for the intersections, and $f$ is somewhere else? Ah, $f$ is in the pentagon. The label near the bottom left intersection is $g$ and $h$.
So: $d=70, e=40, g=110, h=70$.

4. Middle Right (Quadrilateral)
* Angle $j^\circ$: Angles on a straight line. $j = 180 - 120 = 60$.
* Angle $l^\circ$: Sum of angles in a quadrilateral is $360^\circ$. We have $90$ (square symbol), $120$, and $j=60$. Wait, the $120$ is exterior. The interior is $60$. The angle labeled $20^\circ$? No, that's $20^\circ$ inside? No, it says $20^\circ$ near a vertex. Let's look closer. It looks like a right-angled trapezoid or general quad.
Vertices: Top-Left ($90^\circ$), Top-Right (unknown, let's call it $TR$), Bottom-Right ($l$), Bottom-Left ($j$'s neighbor?).
Let's trace the perimeter.
Angle at top left is $90^\circ$.
Angle at bottom left: Exterior is $120^\circ$, so interior is $60^\circ$.
Angle at top right: There is a small triangle attached? No, it's a single quad. The angle is labeled $20^\circ$? No, that's likely part of a diagonal or something. Wait, the label is $20^\circ$ inside the corner? If the interior angle is $20^\circ$, that's very sharp.
Let's re-examine the image. It's a quadrilateral.
Top Left: $90^\circ$.
Bottom Left: Exterior $120^\circ \rightarrow$ Interior $60^\circ$.
Top Right: Labeled $20^\circ$? Or is it $120$? No, the $120$ is bottom left. The top right has a label $20^\circ$? That seems unlikely for a standard polygon unless it's very skewed.
Let's look at the label $l^\circ$. It's the bottom right interior angle.
Is there a fourth angle? Yes, top right.
Maybe the shape is a triangle? No, 4 sides.
Let's look at the text "20°". It is pointing to the top right angle.
Sum = $360$.
$90 + 60 + 20 + l = 360$.
$170 + l = 360$.
$l = 190$. This would be a reflex angle, which doesn't match the drawing (convex quad).
Alternative interpretation: The $20^\circ$ is not the whole angle. Maybe it's the difference?
Let's look at the diagonal. There is a line drawn from bottom-left to top-right.
Ah, it's two triangles? Or a quad with a diagonal?
If it's a quad with a diagonal, we need more info.
Let's look at the label $l^\circ$ again. It's an interior angle.
Let's look at the top right angle again. It says $20^\circ$. And there is a right angle symbol at the top left.
Maybe the $20^\circ$ is the angle between the diagonal and the top side?
If so, we can't solve it without more info.
Let's reconsider the shape. Is it a parallelogram? No.
Let's look at the bottom right angle $l$.
Is it possible the top right angle is NOT $20$?
Let's look at the similar problem structure.
Maybe the $20^\circ$ is an exterior angle? No.
Let's assume the question implies the sum of angles.
What if the top right angle is $90+20$? No.
Let's look at the "clues".
Clue: Parallel lines? No arrows.
Let's skip and come back.

5. Bottom Left (Star/Triangle overlap)
* Angle $o^\circ$: Exterior angle of a triangle. The triangle has interior angles $110$? No, $110$ is obtuse. The angle adjacent to $110$ is $70$.
Let's identify the triangle containing $o$.
The vertices are: Top ($o$), Bottom Left ($110$ exterior?), Bottom Right.
The angle labeled $110^\circ$ is an exterior angle to the triangle at the bottom left vertex. So the interior angle is $180 - 110 = 70^\circ$.
The angle labeled $40^\circ$ is the interior angle at the bottom right? No, it's vertically opposite to an angle inside?
Let's look at the "bowtie" or intersecting triangles.
There are two triangles meeting at a central point.
Left Triangle: Top angle $o$. Bottom-left angle: The exterior is $110$, so interior is $70$. Center angle: Vertically opposite to the right triangle's center angle.
Right Triangle: Bottom-right angle $40$? No, the $40$ is outside.
Let's look at the lines. Two lines intersect.
One line goes from top-left to bottom-right.
One line goes from top-right to bottom-left.
This forms two vertical triangles.
Left Triangle angles: $o$, angle at bottom-left, angle at center.
Right Triangle angles: angle at top-right, angle at bottom-right, angle at center.
We are given:
- Exterior angle at bottom-left of Left Triangle is $110^\circ$. So interior is $70^\circ$.
- Angle at bottom-right of Right Triangle is $40^\circ$? The arc is inside. So interior is $40^\circ$.
- Angle at top-right of Right Triangle is... not given.
- Angle $p$? No, $p$ is in the next shape.
- Angle $o$ is the top angle of the Left Triangle.
We need the center angle.
Wait, look at the Right Triangle. Do we know the top-right angle?
There is a label $40^\circ$ at the bottom right.
There is a label $110^\circ$ at the bottom left (exterior).
Is there a relationship between the two triangles?
Usually, in these "bowtie" problems, if the horizontal lines are parallel, alternate interior angles are equal. But there are no parallel markers.
However, look at the angle labeled $40^\circ$. It is vertically opposite to the angle inside the left triangle? No.
Let's look at the big picture.
Maybe it's one big triangle with a line through it?
Let's assume the vertical-ish lines are straight.
Angle $o$ + Interior Bottom-Left ($70$) + Center Angle = $180$.
We need the Center Angle.
Center Angle = Vertically Opposite to Center Angle of Right Triangle.
Right Triangle Sum: Top-Right + Bottom-Right ($40$) + Center = $180$.
We have two unknowns: $o$ and Top-Right.
Is there a clue I'm missing?
Ah, look at the angle labeled $40^\circ$. Is it possible that the angle vertically opposite to it is in the left triangle?
If the lines are straight, the angle vertically opposite to the $40^\circ$ (bottom-right) is the top-left angle of the right triangle? No.
The angle vertically opposite to the bottom-right angle ($40$) is the top-left angle of the... wait.
Let's name the intersection $C$.
Triangle 1 (Left): Vertices $A$ (top), $B$ (bottom left), $C$ (center).
Triangle 2 (Right): Vertices $D$ (top right), $E$ (bottom right), $C$ (center).
We know $\angle B_{interior} = 70$.
We know $\angle E = 40$.
We want $\angle A = o$.
We know $\angle ACB = \angle DCE$ (vertically opposite).
In $\triangle ABC$: $o + 70 + \angle ACB = 180 \Rightarrow \angle ACB = 110 - o$.
In $\triangle DEC$: $\angle D + 40 + \angle DCE = 180 \Rightarrow \angle DCE = 140 - \angle D$.
So $110 - o = 140 - \angle D \Rightarrow \angle D = o + 30$.
This doesn't give a specific number.
Is there a parallel line?
Look at the top line segment and bottom line segment. They look parallel. If they are parallel, then Alternate Interior Angles are equal.
Transversal $BE$: $\angle B$ ($70$) and $\angle E$ ($40$) are alternate interior? No, they are on the same side? No, opposite sides of transversal. If lines $AD$ and $BE$ were parallel... no.
If Top Line ($AD$) // Bottom Line ($BE$?? No, $B$ and $E$ are points).
If the line containing $A-D$ is parallel to the line containing $B-E$?
Then Alternate Interior Angles for transversal $AB$? No.
For transversal $AE$?
Let's assume the horizontal-ish lines are parallel.
Transversal is the line from Top-Left to Bottom-Right.
Angle at Top-Left ($o$?) No, $o$ is inside.
Let's look at the Z-shape formed by the parallel lines and the transversal connecting Bottom-Left to Top-Right.
Angle at Bottom-Left ($70$) and Angle at Top-Right ($\angle D$) are Alternate Interior Angles.
So $\angle D = 70$.
If $\angle D = 70$, then in Right Triangle: $70 + 40 + \angle C = 180 \Rightarrow \angle C = 70$.
Then in Left Triangle: $o + 70 + 70 = 180 \Rightarrow o = 40$.
Let's check the other transversal (Top-Left to Bottom-Right).
Angle at Top-Left ($\angle A = o = 40$) and Angle at Bottom-Right ($40$) are Alternate Interior Angles.
Yes! $40 = 40$.
So the assumption that the top and bottom lines are parallel is consistent and likely intended.
So $o = 40$.

6. Middle Bottom (Arrowhead/Polygon)
* Angle $p^\circ$: This is a non-convex quadrilateral (arrowhead).
Sum of interior angles is still $360^\circ$? No, for any simple quadrilateral, sum is $360$.
The interior angles are:
1. Reflex angle at the "indentation"? Or do we use the exterior angle theorem for arrowheads?
Rule: The reflex angle = sum of the other three interior angles? No.
Rule: The interior angle at the indentation (reflex) + the other 3 = $360$.
Alternatively, the angle pointing "in" ($p$) is related to the others.
Let's draw a line to split it into two triangles.
Or use the formula: $p = \text{Sum of the three pointed angles}$?
Let's verify. Extend the sides of the "V" to form a triangle.
The exterior angle of the small triangle at the tip is equal to sum of opposite interiors.
Standard Arrowhead Theorem: The reflex angle is $360 - p$.
The sum of the 4 interior angles is $360$.
The angles are: $140^\circ$, $80^\circ$ (implied? No, let's read the labels).
Labels:
- Left tip: $140^\circ$? No, that's obtuse. The angle inside is $140$?
- Top tip: Unknown.
- Bottom tip: Unknown.
- Indented angle: $p$.
Wait, the label $140^\circ$ is at the left vertex.
There are tick marks on the top and bottom sides? No.
There is a label $80^\circ$? No.
Let's look at the shape again.
It has 4 vertices.
Left vertex: $140^\circ$.
Top vertex: Let's call it $T$.
Bottom vertex: Let's call it $B$.
Right vertex (indent): $p$.
Are there other numbers?
I see a label "80°" near the top vertex? No.
I see a label "30°"? No.
Let's look at the previous column.
Ah, I missed the labels on the Arrowhead.
Left angle: $140^\circ$.
Top angle: Looks like a right angle? No mark.
Bottom angle: Looks like a right angle? No mark.
Wait, look at the tick marks.
Top side and Bottom side have single ticks. They are equal length.
Left side and... no.
Is it a kite? If it's a kite, top and bottom angles are equal.
If it's a kite, the axis of symmetry is horizontal.
Then Top Angle = Bottom Angle.
Let's call them $y$.
Sum of angles: $140 + y + y + \text{Reflex } P = 360$?
No, $p$ is the interior angle shown? The arc for $p$ is inside the "mouth". So $p$ is the reflex angle?
Usually, variables like $p$ refer to the angle less than $180$ unless indicated. The arc for $p$ is clearly the interior angle facing left, which is less than $180$.
So the interior angle at the indentation is $p$.
The sum of interior angles of a concave quad is still $360$?
Let's check. Split into two triangles. Sum = $180 + 180 = 360$.
So $140 + \text{Top} + \text{Bottom} + p = 360$.
If it is a kite (symmetric), Top = Bottom.
Do we know Top?
Look at the label near the top vertex. It says "80°"?
Let me zoom in on the original image crop.
Crop 5 shows the arrowhead.
Label at left: $140^\circ$.
Label at top: It looks like there is no number.
Label at bottom: No number.
Label at indent: $p^\circ$.
Is there a parallel marker?
Top and bottom sides have ticks. Left and... no.
Wait, look at the angle arcs.
Top and Bottom angles have single arcs. Left has double? No.
If Top and Bottom angles are marked identical, they are equal.
We still need one value.
Is it possible the shape is composed of specific triangles?
Let's look at the label "80°" I thought I saw.
In the full image, between the arrowhead and the triangle below it, there is no text.
Inside the arrowhead, near the top vertex, is there a number?
It looks like "80°" is written near the top vertex.
Let's assume Top Angle = $80^\circ$.
If Top = $80$, and by symmetry/markings Bottom = $80$.
Then $140 + 80 + 80 + p = 360$.
$300 + p = 360$.
$p = 60$.

7. Bottom Middle (Parallel Lines with Transversals)
* Angle $q^\circ$:
Two parallel horizontal lines.
A zig-zag transversal.
Top angle: $40^\circ$ (acute, between parallel and transversal).
Middle angle: $q^\circ$ (obtuse, pointing left).
Bottom angle: $30^\circ$ (acute, between parallel and transversal).
Rule for Zig-Zag: Sum of left-pointing angles = Sum of right-pointing angles.
Left-pointing: $q$.
Right-pointing: $40 + 30 = 70$.
So $q = 70$?
Wait, look at the orientation.
Top angle $40$ is acute. The "point" is to the right? No, the vertex is on the top line. The angle is inside.
Let's draw a parallel line through the middle vertex $q$.
Alternate interior angle from top: $40^\circ$.
Alternate interior angle from bottom: $30^\circ$.
Angle $q$ is the sum of these two parts?
Yes, if $q$ spans the entire opening.
So $q = 40 + 30 = 70$.
*Check*: The diagram shows $q$ as an obtuse angle?
Visually, $q$ looks obtuse ($>90$). $70$ is acute.
Let's re-read the diagram.
Top angle: $40^\circ$.
Bottom angle: $30^\circ$.
Middle angle: $q^\circ$.
The arc for $q$ is on the *left* side of the vertex.
The angles $40$ and $30$ are on the *right* side of their respective vertices?
Top: Angle is between the parallel line (right side) and transversal.
Bottom: Angle is between the parallel line (right side) and transversal.
Middle: Angle $q$ is between the two transversal segments, on the left.
Using the "pencil tip" rule:
Draw parallel line through $q$.
Top part of $q$ = Alternate Interior to $40$ = $40$.
Bottom part of $q$ = Alternate Interior to $30$ = $30$.
Total $q = 70$.
Why does it look obtuse? Diagrams are "Not to Scale". Trust the math.
$q = 70$.

8. Back to Middle Right (Quad with diagonal?)
Let's re-evaluate the quadrilateral with $j, l$.
We had $j = 60$.
We had a mystery angle $20^\circ$.
If the shape is a parallelogram, opposite angles are equal.
If it's a parallelogram, $j = l$? No, consecutive are supplementary.
If it's a parallelogram, opposite angles are equal.
Angle opposite $j$ ($60$) would be the top-right angle.
If Top-Right is $60$, then $l$ (bottom-right) is supplementary to $60$? No, supplementary to adjacent.
Adjacent to $j$ ($60$) is $l$? No, $j$ is bottom-left. $l$ is bottom-right.
In a parallelogram, consecutive angles sum to $180$.
So $j + l = 180 \Rightarrow 60 + l = 180 \Rightarrow l = 120$.
Does the $20^\circ$ fit?
If it's a parallelogram, Top-Left ($90$) and Bottom-Right ($120$) should be equal? No, opposite angles are equal.
Top-Left ($90$) should equal Bottom-Right ($l$). So $l=90$.
Then Bottom-Left ($60$) should equal Top-Right.
Sum = $90+90+60+60 = 300 \neq 360$. Contradiction.
So it's not a parallelogram.
Let's look at the $20^\circ$ again.
It is located at the top right vertex.
It is likely the angle between the diagonal and the top side.
And there is a right angle at Top-Left.
This implies we might have two triangles.
Triangle 1 (Top): Right angled at Top-Left.
If we assume the diagonal splits the quad...
We need more constraints.
Let's look at the label $l^\circ$ again.
Is it possible the $20^\circ$ refers to the angle $l$? No, $l$ is at the bottom.
Is it possible the top-right angle is $90+20=110$?
Or $90-20=70$?
Let's guess based on common problems.
Often, these are trapezoids.
If Top and Bottom are parallel:
Then Top-Left ($90$) + Bottom-Left ($60$) = $150 \neq 180$. Not parallel.
If Left and Right are parallel:
Top-Left ($90$) + Top-Right = $180 \Rightarrow$ Top-Right = $90$.
Bottom-Left ($60$) + Bottom-Right ($l$) = $180 \Rightarrow l = 120$.
Does the $20^\circ$ fit?
If Top-Right is $90$, and there's a $20^\circ$ label... maybe the diagonal makes a $20^\circ$ angle?
If Top-Right is $90$, and the diagonal makes $20^\circ$ with the top side, then the other part is $70^\circ$.
This doesn't help find $l$ unless we know more about the diagonal.
However, if it's a right trapezoid (Left side perpendicular to bases), then Top-Left=$90$, Bottom-Left=$90$. But Bottom-Left is $60$.
So Left side is not perpendicular to both.
Let's assume the standard "Sum of Angles" approach with the most likely reading of the blurry text.
If the Top-Right angle is simply $20^\circ$ (very sharp):
$90 + 60 + 20 + l = 360 \Rightarrow l = 190$ (Reflex). Unlikely.
If the Top-Right angle is $120^\circ$ (looking at the shape, it's obtuse)?
Where does $20$ come from?
Maybe the angle labeled $20$ is actually $120$?
If Top-Right = $120$:
$90 + 60 + 120 + l = 360 \Rightarrow 270 + l = 360 \Rightarrow l = 90$.
This looks plausible. The corner at $l$ looks somewhat square.
Let's check the Pentagons again to see if I can resolve the ambiguity there, which might inform the style.

Re-evaluating Pentagon (Top Right)
$f, i, k$.
Sum = $540$.
Known: $110, 110, 130$. Sum = $350$.
Remaining: $190$.
$f = k$ (single tick). $i$ (double tick).
If it's a house shape, often $f=k=90$.
If $f=90, k=90$, then $i = 10$.
Visually, $i$ is NOT $10$. $i$ is obtuse.
So $f, k$ are not $90$.
Maybe $i = 110$ (like the others)?
If $i=110$, then $2f = 190 - 110 = 80 \Rightarrow f=40$.
Visually, $f$ and $k$ are obtuse too.
Maybe all remaining are equal? $190 / 3 = 63.3$. No.
Let's look at the ticks again.
$f$ and $k$ have single ticks.
$i$ has a double tick.
The angles labeled $110$ have NO ticks.
The angle labeled $130$ has NO ticks.
This implies $f=k \neq i$.
Is there a geometric property?
Maybe it's a regular pentagon distorted? No.
Let's look at the solution key pattern for these worksheets.
Often, $f$ and $k$ are right angles ($90$) despite the visual.
But $i=10$ is absurd.
What if the $130$ is actually $100$?
$110+110+100 = 320$. Remainder $220$.
If $f=k=90$, $i=40$. Still small.
What if the $110$s are $100$s?
$100+100+130 = 330$. Remainder $210$.
If $f=k=90$, $i=30$.
Okay, let's look at angle $i$ again. It's the top angle.
In many "house" pentagons, the roof angle is distinct.
Let's assume $f=90, k=90$ is the intended answer for the "walls", and calculate $i$.
$i = 540 - (110+110+130+90+90) = 540 - 530 = 10$.
This is mathematically consistent with the "right angle walls" trope, even if drawn poorly.
However, if $f$ and $k$ are not $90$, we can't solve it uniquely.
Given the "Not to Scale" warning, we must trust markings over visuals.
Are $f$ and $k$ marked as right angles? No square symbol.
But they are marked equal.
Is there any other constraint?
Let's leave $f,k,i$ as dependent.
Wait! Look at the quadrilateral below the pentagon.
Maybe the answers are integers.
Let's try $f=100, k=100, i= -10$? No.
Let's try $f=80, k=80, i=30$?
Let's try $f=95, k=95, i=0$?
There is a possibility that the $130$ is an exterior angle?
If $130$ is exterior, interior is $50$.
Sum = $110+110+50 = 270$.
Remainder = $270$.
If $f=k=90$, $i=90$.
This creates a pentagon with three $90$s and two $110$s?
$90+90+90+110+110 = 490 \neq 540$.
If interior is $50$:
$110+110+50+f+k+i = 540$.
$270 + 2f + i = 540 \Rightarrow 2f + i = 270$.
If $f=90$, $180+i=270 \Rightarrow i=90$.
This yields $f=90, k=90, i=90$.
This is a very clean solution.
Does the $130$ look like an exterior angle?
The arc is inside the polygon. So it's interior.
So this theory is weak.

Let's go with the most standard interpretation of such diagrams where ticks imply equality and lack of other info implies right angles for "vertical" walls if they look vertical.
But $i=10$ is bad.
Let's look at Angle $m, n$ (Triangle below Quad).
Triangle with exterior angles.
Interior angles:
Top: $60$? No, label is $60$ inside.
Bottom Left: Exterior $120$? No, label $120$ is inside?
Label $120$ is inside. Label $60$ is inside.
Third angle = $180 - 120 - 60 = 0$. Impossible.
So $120$ must be exterior.
If $120$ is exterior, interior is $60$.
Then Triangle is Equilateral ($60, 60, 60$).
Then exterior angles $m$ and $n$?
$m$ is exterior to the $60$ (top)? $m = 120$.
$n$ is exterior to the bottom right ($60$)? $n = 120$.
This works perfectly.
So $m=120, n=120$.

Back to Quad ($j, l$).
If the triangle below it is equilateral, maybe the quad is a standard type.
If $l=90$ and Top-Right=$120$?
$90+60+120+90 = 360$.
This requires Top-Right to be $120$.
The label "20" is the problem.
Could "20" be part of "120"? Like the '1' is faint?
Or is it $70$? ($90-20$).
If Top-Right = $70$:
$90+60+70+l = 360 \Rightarrow 220+l=360 \Rightarrow l=140$.
If Top-Right = $100$?
$90+60+100+l = 360 \Rightarrow l=110$.

Let's look at Angle $r, s, t$ (Bottom Row).
Left ($r$):
Triangle with exterior angle.
Interior: $50$ (bottom left), $60$ (top? No, $60$ is exterior?).
Label $60$ is at the top vertex, outside. So exterior = $60$. Interior = $120$.
Label $50$ is inside.
Third angle (bottom right) = $180 - 120 - 50 = 10$.
Angle $r$ is exterior to this third angle?
$r = 180 - 10 = 170$.
Or is $r$ the exterior angle equal to sum of opposites?
$r = 120 + 50 = 170$.
So $r = 170$.

Middle ($s$):
Parallel lines?
Transversal cuts parallel lines.
Angle $140$ is interior.
Angle $s$ is interior on the same side?
If parallel, consecutive interior sum to $180$.
$s + 140 = 180 \Rightarrow s = 40$.
So $s = 40$.

Right ($t$):
Triangle with vertical angles.
Top angle: $20$? No, $20$ is exterior?
Label $20$ is at the top, between the vertical line and the triangle side.
Label $30$ is at the bottom left, inside.
Label $t$ is at the bottom right, inside.
Vertical line is straight.
Angle at top vertex inside triangle: Vertically opposite to... nothing.
Wait, the vertical line continues through the triangle?
No, it's a side.
There is a vertical line on the left and right?
"Parallel vertical lines" indicated by arrows?
Yes, arrows on the vertical lines.
So Left Side // Right Side.
Transversal is the bottom side? No.
Transversal is the top side?
Angle $20$ is between the left vertical and the top transversal.
So Alternate Interior Angle at the right vertical (top) is $20$.
So the top-right angle inside the triangle is $20$?
No, the triangle is between the parallels.
Let's trace the "Z".
Left vertical, Top transversal, Right vertical.
Angle between Left Vertical and Top Transversal is $20$.
So Angle between Right Vertical and Top Transversal (Alternate Interior) is $20$.
This angle is INSIDE the triangle?
The triangle vertex is on the right vertical line.
So the interior angle at the top right is $20$.
Bottom left interior angle is $30$.
Sum of angles in triangle = $180$.
Third angle (bottom right) = $180 - 20 - 30 = 130$.
Angle $t$ is this interior angle?
The label $t$ is inside the bottom right corner.
So **$t
Parent Tip: Review the logic above to help your child master the concept of geometry lines and angles worksheet.
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