Question

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

Answer 1

$\huge \fbox \red{Answer}$

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

Let the measure of angles be x, y, z.

Therefore, we can write above statement as x = y + z

x + y + z = 180°

Substituting the above value, we get

x + x = 180°

2x = 180°

x = 180/2

x = 90°

If one angle is 90° then the given triangle is a right angled triangle.

Answer 2

Answer:

∠A + ∠B + ∠C = 180

∠A = ∠B + ∠C (Given)

∠B + ∠C + ∠B + ∠C = 180

2 (∠B + ∠C) = 180

∠B + ∠C = 180/2 = 90

∠A + 90 = 180

∠A = 180-90 = 90