Question

Determining the Angles of a Triangle
Which angle measurements can form triangle ABC? Select all that apply.
m∠A = 40°, m∠B = 75°, m∠C = 65°
m∠A = 136°, m∠B = 28°, m∠C = 16°
m∠A = 57°, m∠B = 58°, m∠C = 63°
m∠A = 90°, m∠B = 35°, m∠C = 35°
m∠A = 60°, m∠B = 60°, m∠C = 60°

Answer 1

A triangle's interior angles must be positive and sum to 180°.

- 40° + 75° + 65° = 180° → yes
- 136° + 28° + 16° = 180° → yes
- 57° + 58° + 63° = 178° → no
- 90° + 35° + 35° = 160° → no
- 60° + 60° + 60° = 180° → yes

So the valid sets are the 1st, 2nd, and 5th.