Question

In a $\Delta ABC$, if AB = AC and $\angle A={70}^{\circ }$, find $\angle B$ and $\angle C$.

Answer 1

Since, AB = AC, therefore, $\angle B=\angle C$

By angle sum property of triangle,

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

${70}^o+2\angle B={180}^o$

$2\angle B={110}^o$

$\angle B={55}^o$

Hence, $\angle B=\angle C={55}^o$