Question

calculate the area of a circular ring enclosed between two circles having radius 6 cm and 12 CM respectively​

Answer 1

Given :-

• A circular ring whose inner radius is 6 cm and outer radius is 12 cm.

To Find :-

• Area of a circular ring

Formula Used :-

Let us consider a circular ring having inner radius 'r' units and outer radius 'R' units.

Then,

$\bf \: Area_{(ring)} \: = \sf \: \pi \: ( {R}^{2} - {r}^{2} )$

$\large\underline{\bold{Solution-}}$

According to given statement,

• Inner radius, r = 6 cm

• Outer radius, R = 12 cm

So,

Area of circular ring is

$\bf \: Area_{(ring)} = \pi \: ( {R}^{2} - {r}^{2} )$

$\sf \: Area_{(ring)} = \dfrac{22}{7} \bigg( {(12)}^{2} - {(6)}^{2} \bigg)$

$\sf \: Area_{(ring)} = \dfrac{22}{7} \times (12 + 6) \times (12 - 6)$

$\sf \: Area_{(ring)} = \dfrac{22}{7} \times 18 \times 6$

$\therefore \: \: \sf \: Area_{(ring)} = \dfrac{2376}{7} \: {cm}^{2}$

Additional Information :-

$\boxed{ \bf{Area_{(circle)} = \pi \: {r}^{2} }}$

$\boxed{ \bf{Area_{(rectangle)} = length \times breadth}}$

$\boxed{ \bf{Area_{(square)} = {(side)}^{2} }}$

$\boxed{ \bf{Area_{(parallelogram)} = base \times height}}$

$\boxed{ \bf{Area_{(triangle)} = \dfrac{1}{2} \times base \times height}}$