Question

If one angle of a triangle is equal to half the sum of the other two equal angles, the triangle is

• A. equilaterial
• B. isosceles
• C. right angled
• D. isosceles right angled

Answer 1

The correct option is A equilaterial

Given one angle of a triangle is equal to half the sum of the other two equal angles.

Let the angles be $\alpha ,\beta$

Then, $\alpha =\frac{1}{2}(\beta +\beta )=\beta$

but $\alpha +2\beta =180°$

$⟹\alpha =\beta =60°$

$\therefore$ It is an equilateral triangle.