Question

The difference between circumference and radius of a circle is $37m$. The circumference of that circle is

• A. $7m$
• B. $44m$
• C. $154m$
• D. none

Answer 1

Answer: (B)

Let the radius of the circle be' $r$' .

$\Rightarrow$ Circumference of a circle $=2\pi r$

Since, the difference between circumference of a circle and its radius is $37m$.

$\Rightarrow 2\pi r-r=37m$

$\Rightarrow r(2\pi -1)=37m$

$\Rightarrow r(2\times \frac{22}{7}-1)=37m$

$\Rightarrow r(\frac{44}{7}-1)=37m$

$\Rightarrow r\left(\frac{44-7}{7}\right)=37m$

$\Rightarrow r\left(\frac{37}{7}\right)=37m$

$\Rightarrow r=\frac{7}{37}\times 37m$

$\Rightarrow r=7m$

$\Rightarrow$ The circumference of the circle $=2\pi r$

$=2\times \frac{22}{7}\times 7m$

$=44m$

Therefore, he circumference of the circle is $44m$.

Hence, Option B is correct.