Question

Two concentric circle have radii of 14 cm and 7 cm respectively.Find the area of space between them.

Answer 1

firstly r of the one circle be 14 and another be 7 cm
area of circle witd r 7cm=πrsq
22÷7×7×7 =154
area of circle with r 14 cm =πr sq.
22÷7×14×14=616
now,the space btwn the circle are
area of first circle -area of second circle
616-154=462cm

Answer 2

Given :

We have Two concentric circles of Radius 14cm and 7cm.

To Find:

We have to find the area of space between these circle?

Step-by-step explanation:

• Since, We have Two concentric circles, We know two circle are said to be concentric when they have the same centre.

• Let the radius of small circle be ,OB=7cm
• Let the radius of big circle be ,OA=14cm   (see the attach fig.)
• Now area of big circle is given by the formula
• $Area=\pi r^2$

• We have radius of big circle is OA=14cm

      $\textrm{Area of big circle}=\pi (OA)^2\\\textrm{Area of big circle}=\frac{22}{7} (14)^2\\\\\textrm{Area of big circle}=22\times2\times14=616cm^2$

• Now area of small circle is given by the formula

      $Area=\pi r^2$

• We have radius of big circle is OB=7cm

     $\textrm{Area of small circle}=\pi (OB)^2\\\textrm{Area of small circle}=\frac{22}{7} (7)^2\\\\\textrm{Area of big circle}=22\times7=154cm^2$

• Hence Area of space between two circle is same as area of shaded portion in the given figure hence area of shaded portion is given by the formula

      $\textrm{Area of shaded portion}=\textrm{Area of big circle}-\textrm{Area of small circle}$

• Now put the values in above equation

     $\textrm{Area of space between circle}=616-154=462cm^2$

Hence, area of space between them is 462$cm^2$.