Let’s solve each triangle one by one. Remember:
the three angles in any triangle always add up to 180°. We’ll use that rule for every problem.
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Problem 1 (top left):
Right triangle with angle A = 90°, angle B = 22°, find angle C = x.
→ 90 + 22 + x = 180
→ 112 + x = 180
→ x = 180 - 112 =
68
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Problem 2 (top middle):
Equilateral triangle? Wait — all sides have tick marks, so it’s equilateral → all angles equal.
But wait — actually, only two sides are marked equal on the legs, and base also has a mark — yes, all three sides equal → equilateral → each angle is 60°.
So x =
60
Wait — let me double-check: if all sides are equal, then all angles are equal. 180 ÷ 3 = 60. Yes.
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Problem 3 (top right):
Isosceles triangle — two sides equal (marked), so base angles are equal.
Angle at A = 55°, so angle at C is also 55°.
Then angle at B = x.
→ 55 + 55 + x = 180
→ 110 + x = 180
→ x =
70
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Problem 4:
Triangle with angles: A = 68°, B = 52°, C = x
→ 68 + 52 + x = 180
→ 120 + x = 180
→ x =
60
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Problem 5:
Right triangle at A (90°), angle B = 43°, find angle C = x
→ 90 + 43 + x = 180
→ 133 + x = 180
→ x =
47
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Problem 6:
Angles: A = 52°, B = 74°, C = x
→ 52 + 74 + x = 180
→ 126 + x = 180
→ x =
54
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Problem 7:
Angles: A = 82°, B = 22°, C = x
→ 82 + 22 + x = 180
→ 104 + x = 180
→ x =
76
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Problem 8:
Right triangle at A (90°), angle C = 64°, find angle B = x
→ 90 + 64 + x = 180
→ 154 + x = 180
→ x =
26
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Problem 9:
Angles: A = 49°, B = 54°, C = x
→ 49 + 54 + x = 180
→ 103 + x = 180
→ x =
77
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Final Answer:
1. 68
2. 60
3. 70
4. 60
5. 47
6. 54
7. 76
8. 26
9. 77
Parent Tip: Review the logic above to help your child master the concept of angles of triangle worksheet.
