Question

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

please give me fast answer

Answer 1

Let "a" be the measure of the angle A;

Let "b" be the measure of the angle B;

Let "c" be the measure of the angle C.

Then

a + b + c = 180, (1)

a + b = c. (2) (given).

Add the equation (1) and (2). You will get

2(a+b) + c = 180 + c.

Simplify:

2(a+b) = 180 ---> a + b = 180/2=90

C=90