Question

Find n ,if $\angle A=11n-{13}^{\circ }$ and $\angle B=7n+{39}^{\circ }$,where A and B are vertically opposite angles.

• A. ${52}^{\circ }$
• B. ${13}^{\circ }$
• C. ${130}^{\circ }$
• D. ${14}^{\circ }$

Answer 1

Answer: (B)

${13}^{\circ }$

$\angle A=\angle B$ (Vertically opp. angles)
$\Rightarrow 11n-{13}^{\circ }=7n+{39}^{\circ }$
$\Rightarrow 11n-7n={39}^{\circ }+{13}^{\circ }$
$\Rightarrow 4n={52}^{\circ }$
$\Rightarrow n={13}^{\circ }$