Question

A is directly proportional to B squared
When A= 500, B = 10.
Find A when B= 20.

Answer 1

A = 2000.

Explanation:

A = kB^2 where k is a constant to be found, so substituting:

500 = k * 10^2

100k = 500

k = 5.

So we have

A = 5B^2

When B = 20:

A = 5 * 20^2

= 5 * 400

= 2000.