The ratio of the angle is how the angle relates to each other. Let's say that we try to relate Angle A, B, C and get 1 : 3 : 5. That means Angle B is three times Angle A and Angle C is 5 times Angle A
Thus we get the equation:
A
B = 3A
C = 5A
A + B + C = 180, since all the angles of the triangle is equal to 180 degrees
A + 3A + 5A = 180
9A = 180
A = 20 --> B = 3A = 60 --> C = 5A = 100
So Angle A is 20 degrees, Angle B is 60 degrees, and Angle C is 100 degrees.
