Question 343219
let angle B be x
Angle A = 4x
Angle C = x-20
..
x+4x+x-20 =180
6x-20=180
+20
6x=180+20
6x=200
x= 33.33  Angle B
..
Angle A = 4x = 133.32
Angle C =x-20= 13.33
CHECK

33.33 + 133.32 + 13.33