Answer:
102º
Step-by-step explanation:
So you know that ABC is an Isosceles triangle as AB=AC therefore, angle ABC is equal to angle ACB.
You also know that even though it doesn't look like it, ABP is an equilateral triangle as AB, AP and BP are equal so all those angles must equal 60º.
So:
ABC = 60 - 21 = 39º
and since ABC= ACB
ACB also equals 39º.
Because angles in a triangle add to 180º, BAC is consequently:
180- (39+39) = 180 - 78 = 102º
BAC = 102º
