Question

A varies directly as the square of B. If A = 48 when B = 4, then find the constant of variation.

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

The correct option is C 3

Given, A varies directly as the square of B.
$\Rightarrow A\propto B^2$
Let the constant of variation be k.
$\text{Then,}A=k{B}^2$
$\Rightarrow k=\frac{A}{B^2}$
Given, at A = 48, B = 4.
So, $k=\frac{A}{B^2}=\frac{48}{4^2}=\frac{48}{16}=3$.