Question

one of the exterior angles of a triangle is 80 degrees and the interior opposite angles are in the ratio 3 :5 . find the angles of the triangle

Answer 1

Exterior angle = sum of interior opposite angles 

let the interior angles be 3x and 5x

80=3x+5x

80=8x

x= 10

the angles are 30,50

the other angle is 180-(30+50) = 100

Answer 2

Exterior angle = 80 degree
Let on interior angle=3x
other interior angle =5x
3x+5x=80
8x=80
x=10 degree
first angle=30 degree
2nd angle = 50 degree
3rd angle=100 degree