Question

The circumference of a circle is $132cm$ then its diameter is$:$

• A. $14cm$
• B. $42cm$
• C. $30cm$
• D. $20cm$

Answer 1

The correct option is B

$42cm$

It is given that circumference of a circle $=$$132cm$

Circumference of a circle $=2\mathrm{\pi r}$

$2\mathrm{\pi r}=132$

$2\times \frac{22}{7}\times r=132$

$r=\frac{132\times 7}{2\times 22}$

$r=\frac{12\times 7}{2\times 2}$

$r=3\times 7$

$r=21cm$

Diameter $=2\times 21$

$=42cm$

Hence, the diameter of a circle is $42cm$

therefore option $\left(B\right)$ is correct.