Answer:
45°
Explanation:
AB and BC are congruent which mean ∠BAC and ∠BCA are congruent.
We already know ∠ABC is 90°.
We cans set up the equation with what is given.
180 = 90 + 2c
Subtract 90 from both sides.
90 = 2c
Divide both sides by 2
45 = C
So angle C is 45°