Question

Find the fourth proportional to the following:

11, 15, 33

Answer 1

Let x be the fourth proportional

11 : 15 = 33 : x

⇒ `11/15 = 33/x`

⇒ 11x = 15 × 33

⇒ 11x = 495

⇒ x = `495/11`

⇒ x = 45

The fourth proportional is 45.