Question

The radii of two circles are in the ratio of 3 to 1. Find the area of the smaller circle if the area of the larger circle is 27 pi sq. in.

Answer 1

ANSWER
$3\pi sq.\: in.$

EXPLANATION

Let R be the radius of the bigger circle and r, be the radius of the smaller circle.

Then their ratio is given as,

$R:r=3:1$

We can rewrite it as fractions to get,

$\frac{R}{r} = \frac{3}{1}$

We make R the subject to get,

$R = 3r$

The area of the bigger circle can be found using the formula,

$Area=\pi {r}^{2}$

This implies that,

$Area=\pi ({3r})^{2}$

$Area=9\pi {r}^{2}$

But it was given in the question that, the area of the bigger circle is 27π.

$27\pi=9\pi {r}^{2}$

We divide through by 9π to get,

$3 = {r}^{2}$

This means that,
$r = \sqrt{3}$

The area of the smaller circle is therefore

$= \pi {( \sqrt{3}) }^{2}$

$= 3\pi$

Answer 2

Answer:

3(pi)

Step-by-step explanation: