Answer:
The measure of angle A is 30 degrees
Step-by-step explanation:
The addition of the three angles of a triangle must be equal to 180°. Therefore:
∠B + ∠D + ∠E = 180°
∠B + 70° + 50° = 180°
∠B = 180° - 70° - 50°
∠B = 60°
∠B + ∠C + ∠A = 180°
60° + 90° + ∠A° = 180°
∠A = 180° - 90° - 60°
∠A = 30°
