Question

Can someone help me with this?​

Answer 1

∠ A = 72°

Explanation:

The sum of the 3 angles in a triangle = 180°, thus

∠ ECD = 180° - (90 + 54)° = 180° - 144° = 36°

∠ ACB = ∠ ECD = 36° ( vertical angles )

Since AC and BC are congruent then Δ ABC is isosceles, thus the base angles are congruent, that is

∠ A = ∠ B

∠ A =
`(180-36)/(2)` =
`(144)/(2)` = 72°