Question

What is third proportional to 16 and 48 ?

• A. 144
• B. 121
• C. 169
• D. 135

Answer 1

Answer:

A. 144

The third proportional to two numbers (a) and (b) is a number (c) such that:

a : b = b : c

(a = 16)
(b = 48)

$c = \frac{b^2}{a} = \frac{48^2}{16}$

$c = \frac{2304}{16} = 144$
So, the third proportional to 16 and 48 is 144.