Question

ABCD is a parallelogram in which $\angle A=(x+20{)}^{\circ }$ and $\angle C=(3x-10{)}^{\circ }$. Find the value of $x$.

• A. ${60}^{\circ }$
• B. ${40}^{\circ }$
• C. ${30}^{\circ }$
• D. ${15}^{\circ }$

Answer 1

The correct option is D ${15}^{\circ }$

In given figure ABCD is a parallelogram.

We have given that, $\angle A=(x+20{)}^{\circ }$ and $\angle C=(3x-10{)}^{\circ }$

We know that opposite angles of parallelogram are equal.

So, $\angle A=\angle C$

$(x+20{)}^{\circ }=(3x-10{)}^{\circ }$

$2x^{\circ }={30}^{\circ }$

$\therefore$ $x={15}^{\circ }$