Question

In an isosceles triangle, the vertical angle is ${15}^{\circ }$ more than each of its base angles. Find all the angles of the triangle.

Answer 1

$\angle B=\angle C=x$ (isosceles triangle)
$\angle A=\angle B+{15}^{\circ }$
= x+ ${15}^{\circ }$
Now, $\angle A+\angle B+\angle C={180}^{\circ }$
$x+15+x+x={180}^{\circ }$
$3x=165$
$x={55}^{\circ }$