Question

One of the angles of an isosceles triangle is $60°$. What is the measure of the other two angles?

Answer 1

Step I - As one of the isosceles triangle is $60°$.

So, other two angles must be equal to each other because two opposite angles are equal to opposite equal sides.

Step II - Let other two angles be $\text{x, x}$.

As we know that sum of the angles of the triangle is $180°$.

Then, $\text{x + x + 60° = 180°}$

$\text{2x = 180° - 60°}$

$\text{2x = 120°}$

$\text{x = 120° ÷ 2}$

$\text{x = 60°}$

Hence, other two angles are of isosceles triangle are $60°,60°$.