Question

What will be the diameter of a circle whose area is $55.00c{m}^2?$
$(\text{Take}\pi =\frac{22}{7})$

• A. $8cm$
• B. $8.36cm$
• C. $4.2cm$

Answer 1

The correct option is B $8.36cm$

Given: Area of the circle $=55.00c{m}^2$

Area of a circle $=\pi r^2$

$55.00=\frac{22}{7}{r}^2$

$\frac{5500}{100\times 22}=\frac{22}{7\times 22}{r}^2$

$\frac{250\times 7}{100}=r^2$

$\frac{2\times 5\times 5\times 5\times 7}{10\times 10}=r^2$

$2.5\times 7=r^2$

$17.5=r^2$

$r=4.18cm$

Therefore, the diameter will be $2r$ which is equal to $2\times 4.18=8.36cm$.