Let’s solve each triangle one by one.
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Top Left Triangle:
We know two angles: 45° and 70°.
The sum of all angles in a triangle is always 180°.
So, x = 180° - 45° - 70°
x = 65°
✔ Check: 45 + 70 + 65 = 180 → Correct.
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Top Right Triangle:
This triangle has two equal angles labeled “x”, and the top angle is 110°.
So: x + x + 110° = 180°
→ 2x = 180° - 110° = 70°
→ x = 35°
✔ Check: 35 + 35 + 110 = 180 → Correct.
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Bottom Left Triangle:
There’s an exterior angle marked “x” next to interior angle “y”.
The exterior angle equals the sum of the two opposite interior angles.
So: x = 62° + 51° = 113°
Also, since x and y are on a straight line (they form a linear pair), they add up to 180°.
So: y = 180° - x = 180° - 113° = 67°
✔ Check: Interior angles: 62° + 51° + 67° = 180° → Correct.
Exterior angle: 113° = 62° + 51° → Correct.
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Bottom Right Triangle:
We see an exterior angle of 120°, which forms a straight line with angle x.
So: x + 120° = 180° → x = 60°
Now, in the triangle, we have angles: 70°, x (which is 60°), and y.
Sum = 180° → y = 180° - 70° - 60° = 50°
✔ Check: 70 + 60 + 50 = 180 → Correct.
Exterior angle: 120° = 70° + 50° → Also correct (exterior angle = sum of remote interiors).
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Final Answer:
Top left: x = 65°
Top right: x = 35°
Bottom left: x = 113°, y = 67°
Bottom right: x = 60°, y = 50°
Parent Tip: Review the logic above to help your child master the concept of find the missing angle of a triangle worksheet.
