Question

Find the value of x for which the line AB will become parallel to line CD.

• A. $7^{\circ }$
• B. ${10}^{\circ }$
• C. $9^{\circ }$
• D. ${12}^{\circ }$

Answer 1

The correct option is D

${12}^{\circ }$

The line AB will become parallel to line CD, if
$\angle AFG+\angle CGF={180}^{\circ }$
i.e. Co. interior angles are supplementary
$\therefore$ ${84}^{\circ }+9x^{\circ }-{12}^{\circ }={180}^{\circ }9x+{72}^{\circ }={180}^{\circ }9x={108}^{\circ }x={12}^{\circ }$