Geometry Worksheet 6.2 Parallelograms PDF | PDF - Free Printable
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Step-by-step solution for: Geometry Worksheet 6.2 Parallelograms PDF | PDF
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Step-by-step solution for: Geometry Worksheet 6.2 Parallelograms PDF | PDF
Let's solve this Geometry Worksheet on Parallelograms step by step, using the properties of parallelograms.
---
- parallelogram
- congruent
- supplementary
- bisect
---
1. A quadrilateral with two pairs of parallel sides is a parallelogram.
✔ *Definition of a parallelogram.*
2. The opposite sides of a parallelogram are congruent.
✔ *Property: Opposite sides are equal in length.*
3. The opposite angles of a parallelogram are congruent.
✔ *Opposite angles are equal.*
4. The consecutive angles of a parallelogram are supplementary.
✔ *Consecutive angles add up to 180°.*
5. The diagonals of a parallelogram bisect each other.
✔ *Diagonals cut each other into two equal parts.*
---
Given: Parallelogram MATH, with vertices labeled in order (M, A, T, H).
So, sides: MA || HT, MH || AT
Angles: ∠M, ∠A, ∠T, ∠H
6. Name two pairs of congruent angles.
- ∠M ≅ ∠T
- ∠A ≅ ∠H
✔ *Opposite angles are congruent.*
7. Name four pairs of supplementary angles.
Supplementary means they add to 180°. Consecutive angles are supplementary.
- ∠M and ∠A
- ∠A and ∠T
- ∠T and ∠H
- ∠H and ∠M
✔ These are adjacent (consecutive) angles.
8. Name two pairs of congruent segments.
- MA ≅ HT
- MH ≅ AT
✔ *Opposite sides are congruent.*
---
#### Problem 9:
Parallelogram NOPQ
- Given:
- ON = 4
- OP = 6
- ∠N = 32°
We know:
- Opposite sides are congruent → OQ = 4, NP = 6
- Opposite angles are congruent → ∠P = 32°
- Consecutive angles are supplementary → ∠O = 180° − 32° = 148°
So ∠Q = 148°
✔ Label:
- ∠O = 148°
- ∠P = 32°
- ∠Q = 148°
- OQ = 4, NP = 6
---
#### Problem 10:
Parallelogram WXYZ
- Given:
- WX = 7
- XY = 10
- ∠X = 138°
Then:
- Opposite sides: WZ = 10, YZ = 7
- Opposite angles: ∠Z = 138°
- Consecutive angles: ∠W = 180° − 138° = 42°
So ∠Y = 42°
✔ Label:
- ∠W = 42°
- ∠Y = 42°
- WZ = 10, YZ = 7
---
#### Problem 11:
Parallelogram ABCD
- Given:
- AD = 13
- CD = 12
- ∠BAC = 24°
- ∠ACD = 15°
We need to find missing angles.
Note: Diagonal AC is drawn.
Let’s analyze triangle ABC and triangle ADC.
Since ABCD is a parallelogram:
- AB || CD
- AD || BC
- ∠ABC = ∠ADC
- ∠BAD = ∠BCD
But we’re given angles at diagonal AC.
In triangle ABC:
- ∠BAC = 24°
- We can use triangle angle sum or look for relationships.
Wait — notice that diagonal AC divides the parallelogram into two triangles.
Let’s focus on angles around point C:
∠ACD = 15°
But ∠ACD is part of ∠C.
Also, since AB || CD, and AC is transversal, then:
∠BAC and ∠ACD are alternate interior angles → they should be equal?
But here, ∠BAC = 24°, ∠ACD = 15° → not equal? That contradicts unless I misread.
Wait — maybe it's not alternate interior?
Let me draw mentally:
- AB || CD
- AC is diagonal → transversal
Then ∠BAC and ∠ACD are not alternate interior — they are on same side.
Alternate interior would be ∠BAC and ∠ACD only if the transversal cuts both lines — but ∠ACD is inside triangle.
Actually, better approach:
In parallelogram ABCD:
- AB || CD
- AD || BC
Now, consider triangle ABC and triangle CDA.
We are told:
- ∠BAC = 24°
- ∠ACD = 15°
But note: ∠ACD is the same as ∠ACB? No — wait.
Wait, point D is connected to C, so ∠ACD is angle at C between A-C-D.
So ∠ACD = 15° → this is part of angle C.
But angle C = ∠BCD = ∠BCA + ∠ACD?
No — actually, diagonal AC splits ∠C into two parts: ∠ACB and ∠ACD?
Wait — no! In parallelogram ABCD, the vertices are in order: A, B, C, D.
So diagonal AC connects A to C.
Then:
- At vertex C: angle ∠BCD is split by diagonal AC into ∠ACB and ∠ACD? Only if D is on one side.
Wait — actually, from point C, the sides are CB and CD.
So diagonal AC goes from A to C — so it splits angle C into ∠ACB and ∠ACD?
Yes.
So ∠C = ∠ACB + ∠ACD
But we are told ∠ACD = 15°
But we don’t know ∠ACB.
But also, since AB || CD, and AC is transversal:
Then ∠BAC and ∠ACD are alternate interior angles → so they should be equal.
But ∠BAC = 24°, ∠ACD = 15° → not equal → contradiction?
Wait — unless the labeling is different.
Wait — maybe I have the points wrong.
Standard labeling: ABCD in order → A to B to C to D.
So AB || CD, AD || BC.
Diagonal AC.
Now, line AB and line CD are parallel.
Transversal AC intersects them.
Then:
- ∠BAC (at A, between AB and AC)
- ∠ACD (at C, between CD and AC)
These are alternate interior angles → should be equal.
But here, ∠BAC = 24°, ∠ACD = 15° → not equal.
That suggests either the diagram is different or there's a mistake.
Wait — perhaps ∠ACD is not the angle at C between CD and AC?
But it is labeled as such.
Wait — maybe the angle given is not ∠ACD, but ∠ACB?
Wait — problem says: "∠ACD = 15°" — so at point C, between A-C-D.
But if AB || CD, then alternate interior angles: ∠BAC and ∠ACD must be equal.
So if ∠BAC = 24°, then ∠ACD must be 24°, not 15°.
But it says 15° → contradiction.
Unless the figure is not standard.
Wait — maybe the angle is not ∠ACD but ∠ACB?
Let me re-read: "15°" is at point C, labeled near C, probably ∠ACB?
Wait — the label is at point C, and it says "15°", with arc from AC to BC? Or from AC to DC?
Looking at the image description: "15°" is next to point C, likely between AC and DC → so ∠ACD = 15°.
But then conflict with alternate interior angles.
Alternatively, perhaps the angle at A is not ∠BAC, but something else.
Wait — maybe the 24° is ∠CAD?
But it says ∠BAC = 24°.
Wait — unless the diagonal is BD, not AC?
No — the diagonal is drawn from A to C.
Wait — perhaps I need to re-evaluate.
Alternative idea: Maybe the 24° is not ∠BAC, but ∠CAD?
But the problem says: "24°" at point A, between B-A-C → so ∠BAC = 24°.
And at point C, ∠ACD = 15°.
But in parallelogram, AB || CD → transversal AC → alternate interior angles: ∠BAC and ∠ACD should be equal.
So 24° ≠ 15° → impossible.
So likely, the 15° is not ∠ACD, but ∠ACB?
Wait — let's assume the diagram shows:
At point C, the angle between AC and BC is 15° → so ∠ACB = 15°
Then, since AB || CD, and AC is transversal, then ∠BAC and ∠ACD are alternate interior → so ∠ACD = ∠BAC = 24°
But then ∠C = ∠ACB + ∠ACD = 15° + 24° = 39°
But also, in parallelogram, consecutive angles are supplementary.
So ∠A = ∠BAC + ∠CAD?
Wait — we don't know ∠CAD.
Wait — we know ∠BAC = 24°, but what about ∠CAD?
Wait — diagonal AC divides ∠A into ∠BAC and ∠CAD.
But we don’t know ∠CAD.
But we do know side lengths: AD = 13, CD = 12, and AB = 13 (since opposite), BC = 12.
Wait — no: AD = 13, CD = 12 → so AB = 13, BC = 12
But we need more.
Wait — perhaps use triangle ABC and triangle ADC.
But without more info, maybe we can use the fact that in triangle ABC, we know:
- ∠BAC = 24°
- ∠ACB = 15° → assuming the 15° is ∠ACB
Then in triangle ABC:
- ∠ABC = 180° − 24° − 15° = 141°
Then, since ABCD is parallelogram:
- ∠D = ∠B = 141°
- ∠A = 180° − 141° = 39°
- But ∠A = ∠BAC + ∠CAD = 24° + ∠CAD → so ∠CAD = 15°
Then in triangle ADC:
- ∠DAC = 15°
- ∠ACD = ? → but earlier we said ∠ACD = 24° (from alternate interior), but now we have ∠ACB = 15°, so ∠C = 15° + ∠ACD = ?
Wait — if ∠C = 15° + ∠ACD, and ∠C = 141°? No — ∠C = ∠B = 141°? Wait no.
Earlier: ∠ABC = 141°, so ∠C = 180° − 141° = 39°
Yes!
So ∠C = 39°
And ∠C = ∠ACB + ∠ACD = 15° + ∠ACD → so ∠ACD = 24°
Now, check alternate interior angles: ∠BAC = 24°, ∠ACD = 24° → yes, equal → good.
So the 15° is ∠ACB, not ∠ACD.
So the labeling must be: at point C, the angle between AC and BC is 15° → ∠ACB = 15°
Then ∠ACD = 24°
And ∠C = 15° + 24° = 39°
Then ∠A = 180° − 39° = 141°
But ∠A = ∠BAC + ∠CAD = 24° + ∠CAD → so ∠CAD = 117°
But that seems large.
Wait — no: ∠A is the whole angle at A, which is ∠DAB.
In parallelogram, ∠A + ∠B = 180°
We found ∠B = 141° → so ∠A = 39°
But we have ∠BAC = 24° → so ∠CAD = 39° − 24° = 15°
So ∠CAD = 15°
Now in triangle ADC:
- ∠DAC = 15°
- ∠ACD = 24°
- So ∠ADC = 180° − 15° − 24° = 141°
But ∠ADC = ∠B = 141° → matches.
So everything checks.
So missing angles:
- ∠B = 141°
- ∠D = 141°
- ∠C = 39°
- ∠A = 39°
But ∠A is composed of ∠BAC = 24° and ∠CAD = 15° → total 39°
Now, sides:
- AB = 13 (since AD = 13, opposite)
- BC = 12 (CD = 12, opposite)
- All sides known.
So just label:
- ∠A = 39°, ∠B = 141°, ∠C = 39°, ∠D = 141°
- ∠CAD = 15°, ∠ACB = 15°, etc.
But the question asks to find missing angles and sides and label them.
So:
- ∠B = 141°
- ∠D = 141°
- ∠C = 39°
- ∠A = 39°
- ∠CAD = 15°
- ∠ACB = 15°
- ∠ACD = 24°
- Sides: AB = 13, BC = 12, CD = 12, DA = 13
✔ Label accordingly.
---
#### Problem 12:
Parallelogram EFGH
- Given:
- ∠F = 70°
- ∠H = 20°
- Diagonals intersect at point X
- Markings: diagonals bisect each other (hash marks on diagonals)
So diagonals EG and FH intersect at X.
Hash marks:
- On EG: EX = XG → so diagonals bisect each other → expected
- On FH: FX = XH → same
Also, some hash marks on diagonals suggest equal segments.
But we are given:
- ∠F = 70° → ∠EFG = 70°
- ∠H = 20° → ∠GHE = 20°
But in parallelogram, opposite angles are equal.
So ∠F = ∠H → 70° = 20°? Contradiction.
Wait — unless ∠H is not ∠GHE, but ∠EHG?
Wait — the angle at H is ∠EHG.
But if ∠F = 70°, then ∠H = 70° (opposite angle)
But it says ∠H = 20° → conflict.
Wait — perhaps the 20° is not ∠H, but an angle in triangle?
Look: the diagram shows 20° at point H, between G-H and diagonal.
Wait — the angle marked 20° is likely ∠GHX or ∠CHX?
The marking shows 20° at H, between GH and diagonal.
So it's not the full angle at H.
Similarly, 70° at F, between EF and diagonal.
So likely:
- ∠EFH = 70° → angle between EF and diagonal FH
- ∠GHF = 20° → angle between GH and diagonal FH
Now, in parallelogram EFGH:
- EF || GH
- EH || FG
Diagonal FH connects F to H.
So in triangle EFH and triangle GHF.
But let’s use triangle properties.
At point F: ∠EFH = 70°
At point H: ∠GHF = 20°
Now, since EF || GH, and FH is transversal, then:
- ∠EFH and ∠GHF are alternate interior angles → should be equal?
But 70° ≠ 20° → contradiction.
Wait — no: alternate interior angles would be ∠EFH and ∠GHF only if they are on opposite sides.
Actually, ∠EFH and ∠GHF are on the same side of transversal FH → they are consecutive interior angles → should be supplementary?
But 70° + 20° = 90° ≠ 180° → not supplementary.
So again, conflict.
Wait — perhaps the 70° is ∠EFG, the full angle at F.
And the 20° is ∠GHF, part of angle at H.
But then opposite angles: ∠F = 70°, so ∠H = 70°
But ∠H is split by diagonal into ∠GHF and ∠EHF.
If ∠GHF = 20°, then ∠EHF = 50°
Similarly, at F: ∠EFG = 70°, split by diagonal into ∠EFH and ∠HFG.
But we don't know how it's split.
But we see that diagonals are marked with hash marks: on EG, EX = XG; on FH, FX = XH → so diagonals bisect each other.
Also, the diagonals are shown with tick marks: one on each half, so equal.
Now, the key: in parallelogram, diagonals bisect each other, but not necessarily equal.
Here, we are to find missing angles.
But we have:
- ∠F = 70° → so ∠H = 70°
- ∠E = ∠G = 110° (since consecutive angles are supplementary)
But we are given ∠H = 20°? No — the 20° is not the full angle.
Ah! The 20° is likely the angle between diagonal and side.
So at point H: ∠GHF = 20°
Then, since ∠H = 70°, the other part ∠EHF = 70° − 20° = 50°
Similarly, at F: ∠EFH = 70° → but that’s the full angle? Or part?
Wait — the 70° is labeled at F, between EF and FH → so ∠EFH = 70°
Then, since ∠F = 70°, and it's split by diagonal into ∠EFH and ∠HFG, then ∠HFG = 0°? Impossible.
Wait — unless the 70° is the full angle at F.
But then ∠EFH = 70°, but that would mean the diagonal FH coincides with FG — impossible.
So likely, the 70° is the full angle at F: ∠EFG = 70°
Then, diagonal FH splits it into ∠EFH and ∠HFG.
But we don't know how.
But at H, we have ∠GHF = 20°
Since EF || GH, and FH is transversal, then:
- ∠EFH and ∠GHF are alternate interior angles → so they should be equal.
So ∠EFH = ∠GHF = 20°
But we are told ∠EFH = 70° → conflict.
Wait — unless the 70° is not ∠EFH.
Let me re-express.
Perhaps the 70° is ∠EFG, the full angle at F.
Then, diagonal FH splits it into ∠EFH and ∠HFG.
Similarly, at H, diagonal FH splits ∠GHE into ∠GHF and ∠EHF.
Now, since EF || GH, and FH is transversal, then:
- ∠EFH and ∠GHF are alternate interior angles → so ∠EFH = ∠GHF
But we are given ∠GHF = 20° → so ∠EFH = 20°
Then, since ∠EFG = 70°, then ∠HFG = 70° − 20° = 50°
Similarly, at H: ∠GHE = 70° (since opposite to F), and ∠GHF = 20°, so ∠EHF = 50°
Now, in triangle EFH:
- ∠EFH = 20°
- ∠FEH = ?
- ∠EHF = 50°
Sum = 180° → ∠FEH = 180° − 20° − 50° = 110°
But ∠FEH is part of ∠E.
∠E = 110° (since consecutive to 70°), and ∠FEH = 110° → so the entire angle at E is ∠FEH, meaning no other part — so diagonal doesn't split it.
Similarly, at G: ∠G = 110°
Now, in triangle FGH:
- ∠GHF = 20°
- ∠HFG = 50°
- So ∠FGH = 180° − 20° − 50° = 110°
But ∠G = 110° → so again, entire angle.
So consistent.
So missing angles:
- ∠E = 110°
- ∠G = 110°
- ∠EFH = 20°
- ∠HFG = 50°
- ∠EHF = 50°
- ∠GHF = 20°
And diagonals bisect each other → so EX = XG, FX = XH
✔ Label all.
---
Given:
- DX = 4
- AX = 6
Find:
- BX = ?
- BD = ?
- XC = ?
- AC = ?
Diagram: Parallelogram ABCD, diagonals AC and BD intersect at X.
In parallelogram, diagonals bisect each other.
So:
- AX = XC → since AC is bisected
- BX = XD → since BD is bisected
Given:
- DX = 4 → so BX = 4 (since diagonals bisect)
- Then BD = BX + XD = 4 + 4 = 8
- AX = 6 → so XC = 6
- AC = AX + XC = 6 + 6 = 12
✔ Answers:
- BX = 4
- BD = 8
- XC = 6
- AC = 12
---
#### 1–5:
1. parallelogram
2. congruent
3. congruent
4. supplementary
5. bisect
#### 6–8:
6. ∠M ≅ ∠T and ∠A ≅ ∠H
7. ∠M and ∠A, ∠A and ∠T, ∠T and ∠H, ∠H and ∠M
8. MA ≅ HT and MH ≅ AT
#### 9–12: (as described above — label on diagrams)
#### 13:
- BX = 4
- BD = 8
- XC = 6
- AC = 12
Let me know if you'd like a visual version or explanation of any specific part!
---
Word Bank:
- parallelogram
- congruent
- supplementary
- bisect
---
1–5. Fill in the blanks
1. A quadrilateral with two pairs of parallel sides is a parallelogram.
✔ *Definition of a parallelogram.*
2. The opposite sides of a parallelogram are congruent.
✔ *Property: Opposite sides are equal in length.*
3. The opposite angles of a parallelogram are congruent.
✔ *Opposite angles are equal.*
4. The consecutive angles of a parallelogram are supplementary.
✔ *Consecutive angles add up to 180°.*
5. The diagonals of a parallelogram bisect each other.
✔ *Diagonals cut each other into two equal parts.*
---
6–8. Use parallelogram MATH
Given: Parallelogram MATH, with vertices labeled in order (M, A, T, H).
So, sides: MA || HT, MH || AT
Angles: ∠M, ∠A, ∠T, ∠H
6. Name two pairs of congruent angles.
- ∠M ≅ ∠T
- ∠A ≅ ∠H
✔ *Opposite angles are congruent.*
7. Name four pairs of supplementary angles.
Supplementary means they add to 180°. Consecutive angles are supplementary.
- ∠M and ∠A
- ∠A and ∠T
- ∠T and ∠H
- ∠H and ∠M
✔ These are adjacent (consecutive) angles.
8. Name two pairs of congruent segments.
- MA ≅ HT
- MH ≅ AT
✔ *Opposite sides are congruent.*
---
9–12. Find missing angles and sides. Label on pictures.
#### Problem 9:
Parallelogram NOPQ
- Given:
- ON = 4
- OP = 6
- ∠N = 32°
We know:
- Opposite sides are congruent → OQ = 4, NP = 6
- Opposite angles are congruent → ∠P = 32°
- Consecutive angles are supplementary → ∠O = 180° − 32° = 148°
So ∠Q = 148°
✔ Label:
- ∠O = 148°
- ∠P = 32°
- ∠Q = 148°
- OQ = 4, NP = 6
---
#### Problem 10:
Parallelogram WXYZ
- Given:
- WX = 7
- XY = 10
- ∠X = 138°
Then:
- Opposite sides: WZ = 10, YZ = 7
- Opposite angles: ∠Z = 138°
- Consecutive angles: ∠W = 180° − 138° = 42°
So ∠Y = 42°
✔ Label:
- ∠W = 42°
- ∠Y = 42°
- WZ = 10, YZ = 7
---
#### Problem 11:
Parallelogram ABCD
- Given:
- AD = 13
- CD = 12
- ∠BAC = 24°
- ∠ACD = 15°
We need to find missing angles.
Note: Diagonal AC is drawn.
Let’s analyze triangle ABC and triangle ADC.
Since ABCD is a parallelogram:
- AB || CD
- AD || BC
- ∠ABC = ∠ADC
- ∠BAD = ∠BCD
But we’re given angles at diagonal AC.
In triangle ABC:
- ∠BAC = 24°
- We can use triangle angle sum or look for relationships.
Wait — notice that diagonal AC divides the parallelogram into two triangles.
Let’s focus on angles around point C:
∠ACD = 15°
But ∠ACD is part of ∠C.
Also, since AB || CD, and AC is transversal, then:
∠BAC and ∠ACD are alternate interior angles → they should be equal?
But here, ∠BAC = 24°, ∠ACD = 15° → not equal? That contradicts unless I misread.
Wait — maybe it's not alternate interior?
Let me draw mentally:
- AB || CD
- AC is diagonal → transversal
Then ∠BAC and ∠ACD are not alternate interior — they are on same side.
Alternate interior would be ∠BAC and ∠ACD only if the transversal cuts both lines — but ∠ACD is inside triangle.
Actually, better approach:
In parallelogram ABCD:
- AB || CD
- AD || BC
Now, consider triangle ABC and triangle CDA.
We are told:
- ∠BAC = 24°
- ∠ACD = 15°
But note: ∠ACD is the same as ∠ACB? No — wait.
Wait, point D is connected to C, so ∠ACD is angle at C between A-C-D.
So ∠ACD = 15° → this is part of angle C.
But angle C = ∠BCD = ∠BCA + ∠ACD?
No — actually, diagonal AC splits ∠C into two parts: ∠ACB and ∠ACD?
Wait — no! In parallelogram ABCD, the vertices are in order: A, B, C, D.
So diagonal AC connects A to C.
Then:
- At vertex C: angle ∠BCD is split by diagonal AC into ∠ACB and ∠ACD? Only if D is on one side.
Wait — actually, from point C, the sides are CB and CD.
So diagonal AC goes from A to C — so it splits angle C into ∠ACB and ∠ACD?
Yes.
So ∠C = ∠ACB + ∠ACD
But we are told ∠ACD = 15°
But we don’t know ∠ACB.
But also, since AB || CD, and AC is transversal:
Then ∠BAC and ∠ACD are alternate interior angles → so they should be equal.
But ∠BAC = 24°, ∠ACD = 15° → not equal → contradiction?
Wait — unless the labeling is different.
Wait — maybe I have the points wrong.
Standard labeling: ABCD in order → A to B to C to D.
So AB || CD, AD || BC.
Diagonal AC.
Now, line AB and line CD are parallel.
Transversal AC intersects them.
Then:
- ∠BAC (at A, between AB and AC)
- ∠ACD (at C, between CD and AC)
These are alternate interior angles → should be equal.
But here, ∠BAC = 24°, ∠ACD = 15° → not equal.
That suggests either the diagram is different or there's a mistake.
Wait — perhaps ∠ACD is not the angle at C between CD and AC?
But it is labeled as such.
Wait — maybe the angle given is not ∠ACD, but ∠ACB?
Wait — problem says: "∠ACD = 15°" — so at point C, between A-C-D.
But if AB || CD, then alternate interior angles: ∠BAC and ∠ACD must be equal.
So if ∠BAC = 24°, then ∠ACD must be 24°, not 15°.
But it says 15° → contradiction.
Unless the figure is not standard.
Wait — maybe the angle is not ∠ACD but ∠ACB?
Let me re-read: "15°" is at point C, labeled near C, probably ∠ACB?
Wait — the label is at point C, and it says "15°", with arc from AC to BC? Or from AC to DC?
Looking at the image description: "15°" is next to point C, likely between AC and DC → so ∠ACD = 15°.
But then conflict with alternate interior angles.
Alternatively, perhaps the angle at A is not ∠BAC, but something else.
Wait — maybe the 24° is ∠CAD?
But it says ∠BAC = 24°.
Wait — unless the diagonal is BD, not AC?
No — the diagonal is drawn from A to C.
Wait — perhaps I need to re-evaluate.
Alternative idea: Maybe the 24° is not ∠BAC, but ∠CAD?
But the problem says: "24°" at point A, between B-A-C → so ∠BAC = 24°.
And at point C, ∠ACD = 15°.
But in parallelogram, AB || CD → transversal AC → alternate interior angles: ∠BAC and ∠ACD should be equal.
So 24° ≠ 15° → impossible.
So likely, the 15° is not ∠ACD, but ∠ACB?
Wait — let's assume the diagram shows:
At point C, the angle between AC and BC is 15° → so ∠ACB = 15°
Then, since AB || CD, and AC is transversal, then ∠BAC and ∠ACD are alternate interior → so ∠ACD = ∠BAC = 24°
But then ∠C = ∠ACB + ∠ACD = 15° + 24° = 39°
But also, in parallelogram, consecutive angles are supplementary.
So ∠A = ∠BAC + ∠CAD?
Wait — we don't know ∠CAD.
Wait — we know ∠BAC = 24°, but what about ∠CAD?
Wait — diagonal AC divides ∠A into ∠BAC and ∠CAD.
But we don’t know ∠CAD.
But we do know side lengths: AD = 13, CD = 12, and AB = 13 (since opposite), BC = 12.
Wait — no: AD = 13, CD = 12 → so AB = 13, BC = 12
But we need more.
Wait — perhaps use triangle ABC and triangle ADC.
But without more info, maybe we can use the fact that in triangle ABC, we know:
- ∠BAC = 24°
- ∠ACB = 15° → assuming the 15° is ∠ACB
Then in triangle ABC:
- ∠ABC = 180° − 24° − 15° = 141°
Then, since ABCD is parallelogram:
- ∠D = ∠B = 141°
- ∠A = 180° − 141° = 39°
- But ∠A = ∠BAC + ∠CAD = 24° + ∠CAD → so ∠CAD = 15°
Then in triangle ADC:
- ∠DAC = 15°
- ∠ACD = ? → but earlier we said ∠ACD = 24° (from alternate interior), but now we have ∠ACB = 15°, so ∠C = 15° + ∠ACD = ?
Wait — if ∠C = 15° + ∠ACD, and ∠C = 141°? No — ∠C = ∠B = 141°? Wait no.
Earlier: ∠ABC = 141°, so ∠C = 180° − 141° = 39°
Yes!
So ∠C = 39°
And ∠C = ∠ACB + ∠ACD = 15° + ∠ACD → so ∠ACD = 24°
Now, check alternate interior angles: ∠BAC = 24°, ∠ACD = 24° → yes, equal → good.
So the 15° is ∠ACB, not ∠ACD.
So the labeling must be: at point C, the angle between AC and BC is 15° → ∠ACB = 15°
Then ∠ACD = 24°
And ∠C = 15° + 24° = 39°
Then ∠A = 180° − 39° = 141°
But ∠A = ∠BAC + ∠CAD = 24° + ∠CAD → so ∠CAD = 117°
But that seems large.
Wait — no: ∠A is the whole angle at A, which is ∠DAB.
In parallelogram, ∠A + ∠B = 180°
We found ∠B = 141° → so ∠A = 39°
But we have ∠BAC = 24° → so ∠CAD = 39° − 24° = 15°
So ∠CAD = 15°
Now in triangle ADC:
- ∠DAC = 15°
- ∠ACD = 24°
- So ∠ADC = 180° − 15° − 24° = 141°
But ∠ADC = ∠B = 141° → matches.
So everything checks.
So missing angles:
- ∠B = 141°
- ∠D = 141°
- ∠C = 39°
- ∠A = 39°
But ∠A is composed of ∠BAC = 24° and ∠CAD = 15° → total 39°
Now, sides:
- AB = 13 (since AD = 13, opposite)
- BC = 12 (CD = 12, opposite)
- All sides known.
So just label:
- ∠A = 39°, ∠B = 141°, ∠C = 39°, ∠D = 141°
- ∠CAD = 15°, ∠ACB = 15°, etc.
But the question asks to find missing angles and sides and label them.
So:
- ∠B = 141°
- ∠D = 141°
- ∠C = 39°
- ∠A = 39°
- ∠CAD = 15°
- ∠ACB = 15°
- ∠ACD = 24°
- Sides: AB = 13, BC = 12, CD = 12, DA = 13
✔ Label accordingly.
---
#### Problem 12:
Parallelogram EFGH
- Given:
- ∠F = 70°
- ∠H = 20°
- Diagonals intersect at point X
- Markings: diagonals bisect each other (hash marks on diagonals)
So diagonals EG and FH intersect at X.
Hash marks:
- On EG: EX = XG → so diagonals bisect each other → expected
- On FH: FX = XH → same
Also, some hash marks on diagonals suggest equal segments.
But we are given:
- ∠F = 70° → ∠EFG = 70°
- ∠H = 20° → ∠GHE = 20°
But in parallelogram, opposite angles are equal.
So ∠F = ∠H → 70° = 20°? Contradiction.
Wait — unless ∠H is not ∠GHE, but ∠EHG?
Wait — the angle at H is ∠EHG.
But if ∠F = 70°, then ∠H = 70° (opposite angle)
But it says ∠H = 20° → conflict.
Wait — perhaps the 20° is not ∠H, but an angle in triangle?
Look: the diagram shows 20° at point H, between G-H and diagonal.
Wait — the angle marked 20° is likely ∠GHX or ∠CHX?
The marking shows 20° at H, between GH and diagonal.
So it's not the full angle at H.
Similarly, 70° at F, between EF and diagonal.
So likely:
- ∠EFH = 70° → angle between EF and diagonal FH
- ∠GHF = 20° → angle between GH and diagonal FH
Now, in parallelogram EFGH:
- EF || GH
- EH || FG
Diagonal FH connects F to H.
So in triangle EFH and triangle GHF.
But let’s use triangle properties.
At point F: ∠EFH = 70°
At point H: ∠GHF = 20°
Now, since EF || GH, and FH is transversal, then:
- ∠EFH and ∠GHF are alternate interior angles → should be equal?
But 70° ≠ 20° → contradiction.
Wait — no: alternate interior angles would be ∠EFH and ∠GHF only if they are on opposite sides.
Actually, ∠EFH and ∠GHF are on the same side of transversal FH → they are consecutive interior angles → should be supplementary?
But 70° + 20° = 90° ≠ 180° → not supplementary.
So again, conflict.
Wait — perhaps the 70° is ∠EFG, the full angle at F.
And the 20° is ∠GHF, part of angle at H.
But then opposite angles: ∠F = 70°, so ∠H = 70°
But ∠H is split by diagonal into ∠GHF and ∠EHF.
If ∠GHF = 20°, then ∠EHF = 50°
Similarly, at F: ∠EFG = 70°, split by diagonal into ∠EFH and ∠HFG.
But we don't know how it's split.
But we see that diagonals are marked with hash marks: on EG, EX = XG; on FH, FX = XH → so diagonals bisect each other.
Also, the diagonals are shown with tick marks: one on each half, so equal.
Now, the key: in parallelogram, diagonals bisect each other, but not necessarily equal.
Here, we are to find missing angles.
But we have:
- ∠F = 70° → so ∠H = 70°
- ∠E = ∠G = 110° (since consecutive angles are supplementary)
But we are given ∠H = 20°? No — the 20° is not the full angle.
Ah! The 20° is likely the angle between diagonal and side.
So at point H: ∠GHF = 20°
Then, since ∠H = 70°, the other part ∠EHF = 70° − 20° = 50°
Similarly, at F: ∠EFH = 70° → but that’s the full angle? Or part?
Wait — the 70° is labeled at F, between EF and FH → so ∠EFH = 70°
Then, since ∠F = 70°, and it's split by diagonal into ∠EFH and ∠HFG, then ∠HFG = 0°? Impossible.
Wait — unless the 70° is the full angle at F.
But then ∠EFH = 70°, but that would mean the diagonal FH coincides with FG — impossible.
So likely, the 70° is the full angle at F: ∠EFG = 70°
Then, diagonal FH splits it into ∠EFH and ∠HFG.
But we don't know how.
But at H, we have ∠GHF = 20°
Since EF || GH, and FH is transversal, then:
- ∠EFH and ∠GHF are alternate interior angles → so they should be equal.
So ∠EFH = ∠GHF = 20°
But we are told ∠EFH = 70° → conflict.
Wait — unless the 70° is not ∠EFH.
Let me re-express.
Perhaps the 70° is ∠EFG, the full angle at F.
Then, diagonal FH splits it into ∠EFH and ∠HFG.
Similarly, at H, diagonal FH splits ∠GHE into ∠GHF and ∠EHF.
Now, since EF || GH, and FH is transversal, then:
- ∠EFH and ∠GHF are alternate interior angles → so ∠EFH = ∠GHF
But we are given ∠GHF = 20° → so ∠EFH = 20°
Then, since ∠EFG = 70°, then ∠HFG = 70° − 20° = 50°
Similarly, at H: ∠GHE = 70° (since opposite to F), and ∠GHF = 20°, so ∠EHF = 50°
Now, in triangle EFH:
- ∠EFH = 20°
- ∠FEH = ?
- ∠EHF = 50°
Sum = 180° → ∠FEH = 180° − 20° − 50° = 110°
But ∠FEH is part of ∠E.
∠E = 110° (since consecutive to 70°), and ∠FEH = 110° → so the entire angle at E is ∠FEH, meaning no other part — so diagonal doesn't split it.
Similarly, at G: ∠G = 110°
Now, in triangle FGH:
- ∠GHF = 20°
- ∠HFG = 50°
- So ∠FGH = 180° − 20° − 50° = 110°
But ∠G = 110° → so again, entire angle.
So consistent.
So missing angles:
- ∠E = 110°
- ∠G = 110°
- ∠EFH = 20°
- ∠HFG = 50°
- ∠EHF = 50°
- ∠GHF = 20°
And diagonals bisect each other → so EX = XG, FX = XH
✔ Label all.
---
13. Use parallelogram ABCD to answer:
Given:
- DX = 4
- AX = 6
Find:
- BX = ?
- BD = ?
- XC = ?
- AC = ?
Diagram: Parallelogram ABCD, diagonals AC and BD intersect at X.
In parallelogram, diagonals bisect each other.
So:
- AX = XC → since AC is bisected
- BX = XD → since BD is bisected
Given:
- DX = 4 → so BX = 4 (since diagonals bisect)
- Then BD = BX + XD = 4 + 4 = 8
- AX = 6 → so XC = 6
- AC = AX + XC = 6 + 6 = 12
✔ Answers:
- BX = 4
- BD = 8
- XC = 6
- AC = 12
---
✔ Final Answers:
#### 1–5:
1. parallelogram
2. congruent
3. congruent
4. supplementary
5. bisect
#### 6–8:
6. ∠M ≅ ∠T and ∠A ≅ ∠H
7. ∠M and ∠A, ∠A and ∠T, ∠T and ∠H, ∠H and ∠M
8. MA ≅ HT and MH ≅ AT
#### 9–12: (as described above — label on diagrams)
#### 13:
- BX = 4
- BD = 8
- XC = 6
- AC = 12
Let me know if you'd like a visual version or explanation of any specific part!
Parent Tip: Review the logic above to help your child master the concept of geometry parallelograms worksheet.