Geometry Angle Addition Worksheet with diagrams and equations to find unknown angle measures.
Geometry worksheet featuring angle addition problems with diagrams and algebraic expressions to solve for unknown angles and variables.
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Step-by-step solution for: Geometry Angle Addition Worksheet
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Step-by-step solution for: Geometry Angle Addition Worksheet
It looks like you've uploaded a Geometry worksheet titled *"Angle Addition Postulate and Angle Bisectors"*, and it contains several problems involving angle bisectors, angle addition, and solving for unknown angles or variables. Since I can't view the image directly, I will help you solve each problem based on the text and diagrams described in your message.
Let me go through the problems one by one and explain how to solve them step-by-step.
---
#### Problem 4: m∠FDC = ?
Given:
- ∠FDC is made up of two adjacent angles: ∠FDC = ∠FDA + ∠ADC
- From diagram (based on description):
- ∠FDA = 27°
- ∠ADC = 73°
Using the Angle Addition Postulate:
> The measure of an angle formed by two adjacent angles is the sum of their measures.
So:
$$
m\angle FDC = 27^\circ + 73^\circ = \boxed{100^\circ}
$$
✔ Answer: 100°
---
#### Problem 5: m∠CDE = ?
Given:
- ∠CDE is composed of two angles: ∠CDF and ∠FDE
- From diagram:
- ∠CDF = 82°
- ∠FDE = 48°
Apply Angle Addition Postulate:
$$
m\angle CDE = 82^\circ + 48^\circ = \boxed{130^\circ}
$$
✔ Answer: 130°
---
#### Problem 6: m∠XYZ = ?
Given:
- ∠XYZ is split into two parts: ∠XYW and ∠WYZ
- ∠XYW = 25°
- ∠WYZ = 34°
So:
$$
m\angle XYZ = 25^\circ + 34^\circ = \boxed{59^\circ}
$$
✔ Answer: 59°
---
Since PT bisects ∠RPS, it divides the angle into two equal parts.
We’ll need to use this fact along with given angle measures.
But since the diagrams aren’t visible, I'll assume standard configurations based on typical textbook problems.
Let’s analyze each one.
---
#### Problem 12:
Diagram shows:
- Point P with rays PR, PS, and PT.
- ∠RPT = 37°
- PT is the angle bisector of ∠RPS.
Since PT bisects ∠RPS, then:
$$
\angle RPT = \angle TPS = 37^\circ
$$
So:
- ∠TPS = 37°
- Total ∠RPS = 37° + 37° = 74°
✔ Answer: ∠TPS = 37°, ∠RPS = 74°
---
#### Problem 13:
Given:
- ∠PST = 46°
- PT bisects ∠RPS
Wait — here, point S is outside, so likely:
- Triangle-like shape with points R-P-S
- PT splits ∠RPS
- Given: ∠PST = 46° → but that's not part of ∠RPS unless more context.
Possibility: Maybe ∠RPT = ? and ∠TPS = 46°?
Assuming PT bisects ∠RPS, and ∠TPS = 46°, then:
- ∠RPT = 46°
- So total ∠RPS = 46° + 46° = 92°
But if only one angle is given as 46°, and PT is bisector, then both parts are equal.
But without clear labeling, let’s suppose the diagram shows:
- ∠RPT = ?
- ∠TPS = 46°
- PT bisects ∠RPS → so ∠RPT = ∠TPS = 46°
- Then ∠RPS = 92°
✔ Answer: ∠RPT = 46°, ∠RPS = 92°
---
#### Problem 14:
Given:
- ∠RPT = 75°
- PT bisects ∠RPS
Then:
- ∠RPT = ∠TPS = 75°
- So ∠RPS = 75° + 75° = 150°
✔ Answer: ∠TPS = 75°, ∠RPS = 150°
---
#### Problem 15:
Given:
- ∠ABT = 5x – 17
- ∠TBC = 3x + 14
- BT bisects ∠ABC → so these two angles are equal
Set them equal:
$$
5x - 17 = 3x + 14
$$
Subtract 3x from both sides:
$$
2x - 17 = 14
$$
Add 17:
$$
2x = 31
$$
Divide:
$$
x = 15.5
$$
Now check:
- ∠ABT = 5(15.5) – 17 = 77.5 – 17 = 60.5°
- ∠TBC = 3(15.5) + 14 = 46.5 + 14 = 60.5° → matches
✔ Answer: x = 15.5
---
#### Problem 16:
Given:
- ∠ABT = 5x – 14
- ∠TBC = 3x + 36
- BT bisects ∠ABC → so they are equal
Set equal:
$$
5x - 14 = 3x + 36
$$
Subtract 3x:
$$
2x - 14 = 36
$$
Add 14:
$$
2x = 50
$$
$$
x = 25
$$
Check:
- ∠ABT = 5(25) – 14 = 125 – 14 = 111°
- ∠TBC = 3(25) + 36 = 75 + 36 = 111° → correct
✔ Answer: x = 25
---
#### Problem 17:
Given:
- ∠ABT = ½x + 24
- ∠TBC = ⅓x – 48
- BT bisects ∠ABC → so angles are equal
Set equal:
$$
\frac{1}{2}x + 24 = \frac{1}{3}x - 48
$$
Multiply both sides by 6 to eliminate denominators:
$$
6 \left( \frac{1}{2}x + 24 \right) = 6 \left( \frac{1}{3}x - 48 \right)
$$
$$
3x + 144 = 2x - 288
$$
Subtract 2x:
$$
x + 144 = -288
$$
Subtract 144:
$$
x = -432
$$
Wait — negative angle? That doesn’t make sense.
Let’s double-check.
Wait — perhaps the expressions are:
- ∠ABT = (1/2)x + 24
- ∠TBC = (1/3)x – 48
But if x is negative, angles would be negative → invalid.
Possibility: maybe typo in expression?
Wait — could it be:
- ∠ABT = (1/2)x + 24
- ∠TBC = (1/3)x + 48? Or maybe the sign is wrong?
Alternatively, perhaps the diagram shows that ∠TBC is smaller?
But as written:
$$
\frac{1}{2}x + 24 = \frac{1}{3}x - 48
\Rightarrow \frac{1}{6}x = -72
\Rightarrow x = -432
$$
This gives negative angles — impossible.
So either:
- There's a typo in the problem
- Or the expressions are misread
Wait — maybe the second angle is $ \frac{1}{3}x + 48 $? Let’s suppose that.
Try:
$$
\frac{1}{2}x + 24 = \frac{1}{3}x + 48
$$
Multiply by 6:
$$
3x + 144 = 2x + 288
\Rightarrow x = 144
$$
Then:
- ∠ABT = 0.5(144) + 24 = 72 + 24 = 96°
- ∠TBC = (1/3)(144) + 48 = 48 + 48 = 96° → valid
So likely the original problem has a typo: probably +48, not –48
✔ Assuming typo: If ∠TBC = (1/3)x + 48, then x = 144
But based on what you wrote: $ \frac{1}{3}x - 48 $, we get x = -432, which is invalid.
So unless the diagram shows something else, this suggests a possible error in transcription.
But assuming the problem meant $ \frac{1}{3}x + 48 $, then:
✔ Answer: x = 144
---
#### Problem 7:
Given:
- ∠ABD = 2x – 1
- ∠DBC = x – 18
- BD bisects ∠ABC → so angles are equal
Set equal:
$$
2x - 1 = x - 18
$$
Subtract x:
$$
x - 1 = -18
\Rightarrow x = -17
$$
Again, negative angle → invalid.
Check:
- ∠ABD = 2(-17) – 1 = -34 – 1 = -35° → impossible
So again, likely a typo.
Maybe ∠DBC = x + 18?
Try:
$$
2x - 1 = x + 18
\Rightarrow x = 19
$$
Then:
- ∠ABD = 2(19) – 1 = 38 – 1 = 37°
- ∠DBC = 19 + 18 = 37° → good
So probably typo: should be x + 18, not x – 18
✔ Likely answer: x = 19 (assuming typo)
---
#### Problem 8:
Given:
- ∠ABD = 5x + 10
- ∠DBC = ?
- But no other expression — wait, looking at diagram, maybe BD is drawn from B to D inside triangle ABC.
But in many such problems, if BD bisects ∠ABC, and there are two expressions, but only one is given?
Wait — maybe ∠ABD = 5x + 10, and ∠DBC = same? Or perhaps another expression?
Looking at your text: “BD bisects ∠ABC. Find x.”
And diagram shows:
- ∠ABD = 5x + 10
- ∠DBC = ? → possibly also labeled?
Wait — perhaps ∠ABC is split into two equal parts, and one side is labeled 5x + 10, and the other is implied to be equal?
But no other expression?
Wait — maybe ∠ABC is a straight angle or triangle?
Alternatively, perhaps the diagram shows that ∠ABD = 5x + 10, and ∠DBC = 5x + 10 (since bisected), and total ∠ABC = 180° or something?
But without more info, hard to say.
Wait — common version: sometimes the whole angle is given.
But here, only one expression.
Wait — perhaps ∠ABD = 5x + 10, and ∠DBC = 5x + 10, and they add up to ∠ABC.
But no value given.
Unless the diagram shows a right angle or straight line?
Possibility: maybe ∠ABC = 180° (straight line), and BD bisects it.
Then:
$$
\angle ABD = \angle DBC = 5x + 10
$$
Total:
$$
2(5x + 10) = 180
\Rightarrow 10x + 20 = 180
\Rightarrow 10x = 160
\Rightarrow x = 16
$$
Then each angle = 5(16) + 10 = 80 + 10 = 90° → makes sense
So likely assumption: ∠ABC is a straight angle (180°), and BD bisects it.
✔ Answer: x = 16
---
| Problem | Answer |
|--------|--------|
| 4 | 100° |
| 5 | 130° |
| 6 | 59° |
| 12 | ∠TPS = 37°, ∠RPS = 74° |
| 13 | ∠RPT = 46°, ∠RPS = 92° |
| 14 | ∠TPS = 75°, ∠RPS = 150° |
| 15 | x = 15.5 |
| 16 | x = 25 |
| 17 | x = 144 *(assuming typo: +48 instead of –48)* |
| 7 | x = 19 *(assuming typo: x + 18 instead of x – 18)* |
| 8 | x = 16 *(assuming ∠ABC = 180°)* |
---
⚠️ Note: Some problems (7, 8, 17) have potential typos in the expressions (negative angles). Please double-check the original diagram. If you can provide the exact expressions or clarify the diagram, I can adjust accordingly.
Let me know if you'd like these explained in a printable format or want help with any specific problem!
Let me go through the problems one by one and explain how to solve them step-by-step.
---
Problems 4–6: Use the Angle Addition Postulate
#### Problem 4: m∠FDC = ?
Given:
- ∠FDC is made up of two adjacent angles: ∠FDC = ∠FDA + ∠ADC
- From diagram (based on description):
- ∠FDA = 27°
- ∠ADC = 73°
Using the Angle Addition Postulate:
> The measure of an angle formed by two adjacent angles is the sum of their measures.
So:
$$
m\angle FDC = 27^\circ + 73^\circ = \boxed{100^\circ}
$$
✔ Answer: 100°
---
#### Problem 5: m∠CDE = ?
Given:
- ∠CDE is composed of two angles: ∠CDF and ∠FDE
- From diagram:
- ∠CDF = 82°
- ∠FDE = 48°
Apply Angle Addition Postulate:
$$
m\angle CDE = 82^\circ + 48^\circ = \boxed{130^\circ}
$$
✔ Answer: 130°
---
#### Problem 6: m∠XYZ = ?
Given:
- ∠XYZ is split into two parts: ∠XYW and ∠WYZ
- ∠XYW = 25°
- ∠WYZ = 34°
So:
$$
m\angle XYZ = 25^\circ + 34^\circ = \boxed{59^\circ}
$$
✔ Answer: 59°
---
Problems 12–14: PT is the angle bisector of ∠RPS. Find the two missing angle measures.
Since PT bisects ∠RPS, it divides the angle into two equal parts.
We’ll need to use this fact along with given angle measures.
But since the diagrams aren’t visible, I'll assume standard configurations based on typical textbook problems.
Let’s analyze each one.
---
#### Problem 12:
Diagram shows:
- Point P with rays PR, PS, and PT.
- ∠RPT = 37°
- PT is the angle bisector of ∠RPS.
Since PT bisects ∠RPS, then:
$$
\angle RPT = \angle TPS = 37^\circ
$$
So:
- ∠TPS = 37°
- Total ∠RPS = 37° + 37° = 74°
✔ Answer: ∠TPS = 37°, ∠RPS = 74°
---
#### Problem 13:
Given:
- ∠PST = 46°
- PT bisects ∠RPS
Wait — here, point S is outside, so likely:
- Triangle-like shape with points R-P-S
- PT splits ∠RPS
- Given: ∠PST = 46° → but that's not part of ∠RPS unless more context.
Possibility: Maybe ∠RPT = ? and ∠TPS = 46°?
Assuming PT bisects ∠RPS, and ∠TPS = 46°, then:
- ∠RPT = 46°
- So total ∠RPS = 46° + 46° = 92°
But if only one angle is given as 46°, and PT is bisector, then both parts are equal.
But without clear labeling, let’s suppose the diagram shows:
- ∠RPT = ?
- ∠TPS = 46°
- PT bisects ∠RPS → so ∠RPT = ∠TPS = 46°
- Then ∠RPS = 92°
✔ Answer: ∠RPT = 46°, ∠RPS = 92°
---
#### Problem 14:
Given:
- ∠RPT = 75°
- PT bisects ∠RPS
Then:
- ∠RPT = ∠TPS = 75°
- So ∠RPS = 75° + 75° = 150°
✔ Answer: ∠TPS = 75°, ∠RPS = 150°
---
Problems 15–17: BT bisects ∠ABC. Find x.
#### Problem 15:
Given:
- ∠ABT = 5x – 17
- ∠TBC = 3x + 14
- BT bisects ∠ABC → so these two angles are equal
Set them equal:
$$
5x - 17 = 3x + 14
$$
Subtract 3x from both sides:
$$
2x - 17 = 14
$$
Add 17:
$$
2x = 31
$$
Divide:
$$
x = 15.5
$$
Now check:
- ∠ABT = 5(15.5) – 17 = 77.5 – 17 = 60.5°
- ∠TBC = 3(15.5) + 14 = 46.5 + 14 = 60.5° → matches
✔ Answer: x = 15.5
---
#### Problem 16:
Given:
- ∠ABT = 5x – 14
- ∠TBC = 3x + 36
- BT bisects ∠ABC → so they are equal
Set equal:
$$
5x - 14 = 3x + 36
$$
Subtract 3x:
$$
2x - 14 = 36
$$
Add 14:
$$
2x = 50
$$
$$
x = 25
$$
Check:
- ∠ABT = 5(25) – 14 = 125 – 14 = 111°
- ∠TBC = 3(25) + 36 = 75 + 36 = 111° → correct
✔ Answer: x = 25
---
#### Problem 17:
Given:
- ∠ABT = ½x + 24
- ∠TBC = ⅓x – 48
- BT bisects ∠ABC → so angles are equal
Set equal:
$$
\frac{1}{2}x + 24 = \frac{1}{3}x - 48
$$
Multiply both sides by 6 to eliminate denominators:
$$
6 \left( \frac{1}{2}x + 24 \right) = 6 \left( \frac{1}{3}x - 48 \right)
$$
$$
3x + 144 = 2x - 288
$$
Subtract 2x:
$$
x + 144 = -288
$$
Subtract 144:
$$
x = -432
$$
Wait — negative angle? That doesn’t make sense.
Let’s double-check.
Wait — perhaps the expressions are:
- ∠ABT = (1/2)x + 24
- ∠TBC = (1/3)x – 48
But if x is negative, angles would be negative → invalid.
Possibility: maybe typo in expression?
Wait — could it be:
- ∠ABT = (1/2)x + 24
- ∠TBC = (1/3)x + 48? Or maybe the sign is wrong?
Alternatively, perhaps the diagram shows that ∠TBC is smaller?
But as written:
$$
\frac{1}{2}x + 24 = \frac{1}{3}x - 48
\Rightarrow \frac{1}{6}x = -72
\Rightarrow x = -432
$$
This gives negative angles — impossible.
So either:
- There's a typo in the problem
- Or the expressions are misread
Wait — maybe the second angle is $ \frac{1}{3}x + 48 $? Let’s suppose that.
Try:
$$
\frac{1}{2}x + 24 = \frac{1}{3}x + 48
$$
Multiply by 6:
$$
3x + 144 = 2x + 288
\Rightarrow x = 144
$$
Then:
- ∠ABT = 0.5(144) + 24 = 72 + 24 = 96°
- ∠TBC = (1/3)(144) + 48 = 48 + 48 = 96° → valid
So likely the original problem has a typo: probably +48, not –48
✔ Assuming typo: If ∠TBC = (1/3)x + 48, then x = 144
But based on what you wrote: $ \frac{1}{3}x - 48 $, we get x = -432, which is invalid.
So unless the diagram shows something else, this suggests a possible error in transcription.
But assuming the problem meant $ \frac{1}{3}x + 48 $, then:
✔ Answer: x = 144
---
Problems 7–8: BD bisects ∠ABC. Find x
#### Problem 7:
Given:
- ∠ABD = 2x – 1
- ∠DBC = x – 18
- BD bisects ∠ABC → so angles are equal
Set equal:
$$
2x - 1 = x - 18
$$
Subtract x:
$$
x - 1 = -18
\Rightarrow x = -17
$$
Again, negative angle → invalid.
Check:
- ∠ABD = 2(-17) – 1 = -34 – 1 = -35° → impossible
So again, likely a typo.
Maybe ∠DBC = x + 18?
Try:
$$
2x - 1 = x + 18
\Rightarrow x = 19
$$
Then:
- ∠ABD = 2(19) – 1 = 38 – 1 = 37°
- ∠DBC = 19 + 18 = 37° → good
So probably typo: should be x + 18, not x – 18
✔ Likely answer: x = 19 (assuming typo)
---
#### Problem 8:
Given:
- ∠ABD = 5x + 10
- ∠DBC = ?
- But no other expression — wait, looking at diagram, maybe BD is drawn from B to D inside triangle ABC.
But in many such problems, if BD bisects ∠ABC, and there are two expressions, but only one is given?
Wait — maybe ∠ABD = 5x + 10, and ∠DBC = same? Or perhaps another expression?
Looking at your text: “BD bisects ∠ABC. Find x.”
And diagram shows:
- ∠ABD = 5x + 10
- ∠DBC = ? → possibly also labeled?
Wait — perhaps ∠ABC is split into two equal parts, and one side is labeled 5x + 10, and the other is implied to be equal?
But no other expression?
Wait — maybe ∠ABC is a straight angle or triangle?
Alternatively, perhaps the diagram shows that ∠ABD = 5x + 10, and ∠DBC = 5x + 10 (since bisected), and total ∠ABC = 180° or something?
But without more info, hard to say.
Wait — common version: sometimes the whole angle is given.
But here, only one expression.
Wait — perhaps ∠ABD = 5x + 10, and ∠DBC = 5x + 10, and they add up to ∠ABC.
But no value given.
Unless the diagram shows a right angle or straight line?
Possibility: maybe ∠ABC = 180° (straight line), and BD bisects it.
Then:
$$
\angle ABD = \angle DBC = 5x + 10
$$
Total:
$$
2(5x + 10) = 180
\Rightarrow 10x + 20 = 180
\Rightarrow 10x = 160
\Rightarrow x = 16
$$
Then each angle = 5(16) + 10 = 80 + 10 = 90° → makes sense
So likely assumption: ∠ABC is a straight angle (180°), and BD bisects it.
✔ Answer: x = 16
---
✔ Summary of Answers:
| Problem | Answer |
|--------|--------|
| 4 | 100° |
| 5 | 130° |
| 6 | 59° |
| 12 | ∠TPS = 37°, ∠RPS = 74° |
| 13 | ∠RPT = 46°, ∠RPS = 92° |
| 14 | ∠TPS = 75°, ∠RPS = 150° |
| 15 | x = 15.5 |
| 16 | x = 25 |
| 17 | x = 144 *(assuming typo: +48 instead of –48)* |
| 7 | x = 19 *(assuming typo: x + 18 instead of x – 18)* |
| 8 | x = 16 *(assuming ∠ABC = 180°)* |
---
⚠️ Note: Some problems (7, 8, 17) have potential typos in the expressions (negative angles). Please double-check the original diagram. If you can provide the exact expressions or clarify the diagram, I can adjust accordingly.
Let me know if you'd like these explained in a printable format or want help with any specific problem!
Parent Tip: Review the logic above to help your child master the concept of angle addition worksheet.