Question
Find the interior angles of the following triangles:
✓
Answer
In $\text {ABC}$
$\angle A=110^{\circ}$
$A B=A C$
$\Rightarrow \angle C=\angle B \ldots .($angles opposite to two equal sides are equal$)$
$\Rightarrow \angle C=\angle B....($angles opposite to two equal sides are equal$)$
Now, by angle sum property,
$\angle A+\angle B+\angle C=180^{\circ}$
$\Rightarrow \angle A+\angle B+\angle B=180^{\circ}$
$\Rightarrow 110^{\circ}+2 \angle B=180^{\circ}$
$\Rightarrow 2 \angle B=180-110^{\circ}$
$\Rightarrow 2 \angle B=70^{\circ}$
$\Rightarrow \angle B=35^{\circ}$
$\Rightarrow \angle C=35^{\circ} $
Hence, $\angle B=35^{\circ}$ and $\angle C=35^{\circ}$.
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