Question

THE outer and inner radi of a ring are 6cm and 4cm respectively. Find the area enclosed by 1. outer ring 2.inner ring 3.ring

Answer 1

Given:

The outer and inner radii of a ring are 6cm and 4cm

To Find:

Find the area enclosed by

a) outer ring

b) inner ring

c) ring

Solution:

First, we need to know the formula for the area of a circle i.e.

                                       $Area=\pi r^{2}$

Now we can proceed further to find

a) Area enclosed by the outer ring

The radius of the outer ring is 6cm, putting this in the formula

$Area(A_{1} )=\pi *6^{2} \\=36\pi cm^{2}$

So the area enclosed by the outer ring is 36πsq.cm

b) Area enclosed by the inner ring

The radius of the inner ring is 4cm, putting this in the formula

$Area(A_{2})=\pi *4^{2} \\=16\pi cm^{2}$

So the area enclosed by the inner ring is 16πsq.cm

c) Area enclosed by the ring

To find the area enclosed by the ring we need to subtract the area enclosed by the outer ring from the area enclosed by the inner ring

$Area=A_{1}-A_{2}\\=36\pi -16\pi \\=20\pi cm^{2}$

So the area enclosed by the ring is 20πsq.cm