Question

Given: BC ⊥ CA , Prove: m∠A+m∠B=90°

Answer 1

With points A, B and C a right triangle is formed.

Given that BC ⊥ CA, then m∠C = 90°.

The addition of the angles of a triangle is equal to 180°, therefore:

m∠A + m∠B + m∠C = 180°

Substituting with m∠C = 90°:

m∠A + m∠B + 90° = 180°

m∠A + m∠B = 180° - 90°

m∠A + m∠B = 90°