Question

.In ∆, if BC = AB and ∠B = 800

, find ∠A?​

Answer 1

Answer:

50 degrees

Step-by-step explanation:

Since it's an isocelse triangle the base angles will be equal.

In this triangle:

Vertex angle= Angle B

Base angles= Angle A and C

Vertex angle= 80 degrees

Angle A = Angle C

Angle A + Angle B + Angle C= 180 degrees

2 Angle A + Angle B= 180 degrees

2 Angle A+ 80 degrees= 180 degrees

2 Angle A= 180 degrees- 80 degrees= 100 degrees

Angle A = 50 degrees

Note: Please see the rough diagram. Also In one of the steps I changed it 2 Angle A because angle A and angle C are equal.

(I hope it's helpful)