Question

An exterior angle of a triangle is 120degree and one of the interior opposite angle is 20degree. Find the other two angles of the triangle

Answer 1

An exterior angle of a triangle is equal to the sum of the opposite interior angles.

Ext. Angle = 120

Interior opp. Angle = 20

Hence the other one is 120–20 = 100

We know the measure of two angles, we need the third one.

Measure of the third angle = 180 - (20+100) = 60

Answer: The other two angles are 60 & 100