Answer:
This is an isosceles triangle, meaning it has 2 congruent angles and one other angle.
Looking at this triangle, we know that ∠B = ∠C.
∠B = 57 degrees
All the angles in a triangle add up to 180, so you need to subtract the two values from 180 to get ∠A.
∠A = 180 - 57 - 57
= 66 degrees
Hope this helps!