Question

It is given that ∆ABC ≅ ∆ FDE in which AB = 5 cm, ∠B = 40°, ∠A = 80° and FD = 5 cm. Then, which of the following is true?
(a) ∠D = 60°
(b) ∠E = 60°
(c) ∠F = 60°
(d) ∠D = 80°

Answer 1

(b)​ $\angle E=60°$

$∆ABC\cong ∆FDE$
AB = 5cm, $\angle B=40°,\angle A=80°$ and FD = 5cm

$$\begin{gathered} \mathrm{Then}\angle A+\angle B+\angle C=180° \\ \Rightarrow 80°+40°+\angle C=180° \\ \Rightarrow \angle C=60° \\ Also,\angle C=\angle E \end{gathered}$$
∴ $\angle E=60°$