Question

The difference between the circumference and radius of a circle is 37 cm. Using $\pi =\frac{22}{7}$, find the circumference of the circle.

Answer 1

Let r be the radius of circle.
Difference between circumference and radius of circle = 37 cm
Circumference of circle = 2 $\pi$ r
= 2 $\times$ $\frac{22}{7}$ $\times$ r = $\frac{44}{7}$ $\times$ r
Now,
Difference between circumference and radius of circle = 2 $\pi$ r - r
37 = $\frac{44}{7}$ $\times$ r - r
37 = r($\frac{44}{7}$-1)
37 = r($\frac{44-7}{7}$)
37 = $\frac{37}{7}$ $\times$ r
37 $\times$ $\frac{7}{37}$ = r
r = 7 cm
Now , Circumference of circle = $\frac{44}{7}$ $\times$ r
= $\frac{44}{7}$ $\times$ 7
= 44 cm .
∴ Circumference of circle = 44 cm