Question

Explain why AB and AC are equal in length

Answer 1

see explanation

Explanation:

the sum of the 3 angles in the triangle = 180°

∠ B + 72° + 36° = 180°

∠ B + 108° = 180° ( subtract 108° from both sides )

∠ B = 72°

Then

∠ B = ∠ C = 72°

this means the 2 base angles in Δ ABC are congruent , then the triangle is isosceles with the 2 legs being congruent , that is

AB = AC