Question

A triangle has two angles measuring 90 and 50, calculate the third angle of the triangle.

Answer 1

Answer:

Option (b) is correct.

The measure of third angle of the triangle is 40°

Step-by-step explanation:

Given : Measure of two angles of a triangle as 90° and 50°

We have to find the measure of the third angle of the triangle.

ANGLE SUM PROPERTY OF A TRIANGLE states that the sum of angles of a triangle is always 180°

Let for the given triangle ABC,

With m∠A = 90° and  m∠B = 50°

Then according to angle sum property stated above,

∠A + ∠B + ∠C  = 180°

90° + 50° + ∠C  = 180°

140° + ∠C  = 180°

∠C  = 180° - 140°

Simplify, we get,

∠C  = 40°

Thus, the measure of third angle of the triangle is 40°

Answer 2

Since the sum of angle within a triangle must always be equal to 180° we can say:

α=180-90-50

α=40°