Question

in the given figure $△ABC$ is an isosceles triangle and $\angle B=65$, find $x$.

• A. ${30}^{\circ }$
• B. ${40}^{\circ }$
• C. ${99}^{\circ }$
• D. ${50}^{\circ }$

Answer 1

The correct option is D ${50}^{\circ }$

Since $\Delta ABC$ is on isosceles triangle

$\therefore \angle B=\angle C$

$\therefore \angle B={65}^o$

$\therefore \angle C={65}^o$

$\therefore \angle A+\angle B+\angle C={180}^o$

$\therefore \angle A+{130}^o={180}^o$

$\therefore \angle A={180}^o-{130}^o$

$\therefore \angle A={50}^o$.