Question

11. If one angle of a triangle is equal to the sum of the other two, show that the triangle is right angled.​

Answer 1

Let the larger angle be 2x

The other two angles will be :- x + x

As we know, ( the sum of all angles of a triangle is 180° )

So,

2x + x + x = 180°

4x = 180°

x = 180° / 4

x = 45°

Hence, x = 4°5 so the larger angle = 45 × 2 = 90° ( which is a right angle )

Therefore, it is proved that the triangle is right angled.