Question

In the given figure, $\angle$ACD is an exterior angle of $∆$ABC. $\angle$B = 40^°, $\angle$A = 70^°.

Find the measure of $\angle$ACD.

Answer 1

In $∆$ABC,
∠ACD = ∠A + ∠B (Exterior angle property)
= 70^∘ + 40^∘
= 110^∘
Hence, the measure of $\angle$ACD is 110^∘​.