Two supplementary angles are in the ratio 4:5.
Let us say, the angles are 4a and 5a
Since angle are supplementary angles;
Which implies, 4a + 5a = 180°
9a° = 180°
a = 20°
Therefore, 4a = 4 (20°) = 80° and 5a = 5 (20°) = 100°
Hence, required angles are 80° and 100°.