We are given one angle that is 3 times less than others. Let us assume one angle measure is x degrees and another is 4x. Because x is 3x less than 4x. ( We can check 4x-x= 3x) Sum of complementary angles is 90 degrees. So, we can set up an equation, First angle measure + first angle = 90 degrees. x+4x = 90. Adding x and 4x, we get 5x. So, 5x = 90. Dividing both sides by 5, we get 5x/5 = 90. x= 18. So, one angle is 18 degrees. Another angle = 4x = 4 times 18 = 72 degrees. So, the required angles are of 18 degrees and 72 degrees.