Question

Two angles of a triangle are in the ratio2:5. If the sum of these angles is equal to third angle, then third angle is(in degrees) ?

Answer 1

Let the two angles of the triangle be 2y and 5y.

Then, as per the question, we know

third angle = 2y + 5y = 7y

We know that sum of all the angles of a triangle is 180°

2y + 5y + 7y= 180°

14y = 180°

y = 180

14

y = 12.85

∠1 = 2y = 2 × 12.85 = 25.7°

∠2 = 5y = 5 × 12.85 = 64.25°

∠3 = 7y = 7 × 12.85 = 89.95°