Question

In a trapezium ABCD, AB | | CD. If $\angle A={60}^{\circ }$ then $\angle D$ = ?

• A. ${100}^{\circ }$
• B. ${120}^{\circ }$
• C. ${70}^{\circ }$
• D. ${300}^{\circ }$

Answer 1

The correct option is B ${120}^{\circ }$

Given-

ABCD is a trapezium.

$CD\parallel AB$.

$\angle BAD={60}^o$.

To find out-

$\angle ADC=?$.

Solution-

$CD\parallel AB$ and AD is the transversal.

$\therefore \angle BAD+\angle ADB={180}^o$ ( the sum of the one sided internal angles=${180}^o$.

$\therefore \angle ADB={180}^o-\angle BAD={180}^o-{60}^o={120}^o$.

So $\angle ADB={120}^o$.

Ans- Option B.