Triangles Find Missing Angle worksheet - Free Printable

To solve each problem, we use the Triangle Angle Sum Theorem, which states:

> The sum of the interior angles of any triangle is always 180°.

We’ll go through each triangle one by one.

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Problem 1:

- Triangle ABC with right angle at A (90°), angle B = 22°, angle C = x.
- So:
x = 180° - 90° - 22° = 68°

✔ Answer: x = 68°

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Problem 2:

- Triangle ABC with tick marks on all three sides → equilateral triangle.
- In an equilateral triangle, all angles are equal.
- So:
x = 180° ÷ 3 = 60°

✔ Answer: x = 60°

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Problem 3:

- Triangle ABC with tick marks on AB and BC → isosceles triangle with base AC.
- Base angles are equal → angle A = angle C = 55°.
- So:
x = 180° - 55° - 55° = 70°

✔ Answer: x = 70°

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Problem 4:

- Angles given: B = 52°, A = 68°, C = x.
- So:
x = 180° - 52° - 68° = 60°

✔ Answer: x = 60°

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Problem 5:

- Right triangle at A (90°), angle B = 43°, angle C = x.
- So:
x = 180° - 90° - 43° = 47°

✔ Answer: x = 47°

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Problem 6:

- Angles given: B = 74°, A = 52°, C = x.
- So:
x = 180° - 74° - 52° = 54°

✔ Answer: x = 54°

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Problem 7:

- Angles given: A = 82°, B = 22°, C = x.
- So:
x = 180° - 82° - 22° = 76°

✔ Answer: x = 76°

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Problem 8:

- Right triangle at A (90°), angle C = 64°, angle B = x.
- So:
x = 180° - 90° - 64° = 26°

✔ Answer: x = 26°

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Problem 9:

- Angles given: B = 54°, A = 49°, C = x.
- So:
x = 180° - 54° - 49° = 77°

✔ Answer: x = 77°

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## ✔ Final Answers:

1. 68°
2. 60°
3. 70°
4. 60°
5. 47°
6. 54°
7. 76°
8. 26°
9. 77°

Let me know if you’d like a diagram or step-by-step visual explanation for any of them!