Question

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

Answer 1

let the 3rd interior angle be 180-80=100deg. so by angle sum property 5x +3x +100= 180 degree. therefore 8x=80 therefore x=10 and angle 5x=50 degree and angle 3x =30 degree

Answer 2

let the required number be x
         exterior angle=sum of interior opposite angles
                        80=5x+3x
                        80=8x
                      80/8=x
                          x=10
             the anglesare 5x=50,3x=30