Question

one of the exterior angles of a tringle is 80° and interior opposite angles are equal to each other.What is the measure of each of these equal angles?

Answer 1

if one of the exterior angle is 80 degrees, interior angle on that line will be 100 degree

let the measure of one equal interior angle be x degree

hence,

x + x + 100 =180   (sum of measures of all angles of a triangle is 180 degrees)

2x + 100 = 180

2x = 180-100

2x = 80

x = 80/2

x = 40

hence two measure of equal opposite angle is 40 degrees each