Question

If the circumference of a circle is $66m$ then radius is $:$

• A. $21m$
• B. $10.5m$
• C. $14m$
• D. $20m$

Answer 1

The correct option is B

$10.5m$

Circumference of the circle $=66m$

We know that circumference of the circle $=2\mathrm{\pi r}$

$2\mathrm{\pi r}=66$

$2\times \frac{22}{7}\times r=66$

$r=\frac{66\times 7}{2\times 22}$

$r=\frac{3\times 7}{2}$

$r=\frac{21}{2}$

$r=10.5m$

Hence, the radius of a circle is $10.5m,$ therefore option (B) is correct.