Question

7. There are two concentric circles as shown in the following figure.
The circumference of outer circle is 132 cm and circumference
of the inner circle is 88 cm. Find the differences between their
radii i.e., (R-r).​

Answer 1

Answer:

7

Step wise explanation :

As we know that the circumference of the circle is

2×pi×radius

Now

In outer circle ⭕

Circumference =132cm

Radius =R =?

by formula

Circumference = 2×pi×R

132 =2×22/7×R

(Taking Pi = 22/7)

132 = 44/7 ×R

132×7 = 44×R

924 =44×R

924/44 = R

21 = R

In inner circle ⭕

Circumference = 88cm

Radius = r = ?

by formula

Circumference = 2×pi×r

88 = 2×22/7×r

(Taking pi =22/7 )

88 = 44/7×r

88×7 = 44×r

616 = 44×r

616/44 = r

14. = r

Now substract r form R

R - r =

21 - 14 = 7

( Putting the value of R and r )