Answer:
Angle A = 100°
Angle B = 80°
Explanation:
Supplementary angles sum 180°
Angle A to Angle B ratio is 5:4, you can write that ratio using a factor.
Angle A = 5x
Angle B = 4x
Since the sum is 180°
Angle A + Angle B = 180°
5x + 4x = 180°
9x = 180°
x = 20°
Replacing x = 20°
Angle A = 5(20°) = 100°
Angle B = 4(20°) 80°