Question

If circumference of a circle is $110cm$, then its diameter is

• A. $\cong 25cm$
• B. $\cong 15cm$
• C. $\cong 20cm$
• D. $35cm$

Answer 1

The correct option is D $35cm$

$\Rightarrow$ The circumference of a circle $=110cm$

$\Rightarrow$ $2\pi r=110$

$\Rightarrow$ $2\times \frac{22}{7}\times r=110$

$\Rightarrow$ $r=110\times \frac{7}{22}\times \frac{1}{2}$

$\Rightarrow$ $r=\frac{35}{2}$

$\Rightarrow$ $r=17.5cm$

$\Rightarrow$ Diameter of circle $\left(d\right)=2r=2\times 17.5cm=35cm$