Question

In the given figure, AB || CD, ∠BAD = 30° and ∠ECD = 50°. Find ∠CED.

Answer 1

$AB\parallel CD\text{and}AD$ is the transversal.
$\therefore \angle CDE=\angle BAD=30°\left[\text{Alternate \hspace{0.17em}Interior Angles}\right]$
In $∆CDE$, we have:
$$\begin{gathered} \angle ECD+\angle CDE+\angle CED=180°\left[\text{Sum of the angles of a triangle}\right] \\ \Rightarrow 50°+30°+\angle CED=180° \\ \Rightarrow \angle CED=100° \end{gathered}$$