Question

Find the mean proportional between 4 and 25.

(a) 25

(b) 10

(c) 100

(d) None of these

Answer 1

Solution —

Let the mean proportion be x.

Then, 4 : x :: x : 25

⇒ 4 / x = x / 25

⇒ x² = 4 × 25 = 100

∴x = √100 = 10

So, The correct option is (b)