Question

4. The area of a circle is 616 cm
circumference.
​

Answer 1

Given:-

• Area of Circle = 616cm²

To find:-

• Circumference of Circle

Solution:-

Area of Circle = 616cm²

$:\implies$ πr² = 616

$:\implies\sf \dfrac{22}{7} \times r^2 = 616$

$:\implies\sf r^2 = \cancel{616} \times \dfrac{7}{ \cancel{22}}$

$:\implies\sf r^2 = 196$

Squaring both sides:-

$:\implies\sf \sqrt{r^2} = \sqrt{196}$

$:\implies\sf r = 14cm$

Now,

Circumference of Circle = 2πr

$\sf 2 \times \dfrac{22}{ \cancel{7}} \times \cancel{14}$

$⇢ \sf 2 \times 44$

$⇢ \sf 88\;cm^2$

$\rule{200}3$

Answer 2

$\sf{\huge{\bold{\pink{\bigstar{\boxed{\boxed{Question}}}}}}}$

• The area of a circle is 616 cm
• circumference.

$\sf{\huge{\bold{\pink{\bigstar{\boxed{\boxed{Solution}}}}}}}$

$\sf{\bold{\red{\boxed{area = \pi R^2}}}}$

$\sf 616 = \pi R^2$

$\sf 616 = \dfrac{22}{7} r^2$

$\sf \cancel{616}\times \dfrac{7}{\cancel{22}} = r^2$

$\sf 28 \times 7 = r^2$

$\sf 196 = r^2$

$\sf r = \sqrt{196}$

$\sf r = 14cm$

• now we can find the circumference from the radius .

$\sf{\bold{\red{\boxed{circumference = 2 \pi R}}}}$

$\sf circumference = 2\times \dfrac{22}{\cancel 7}\times \cancel{14}$

$\sf circumference = 2 \times 22 \times 2$

$\sf circumference = 4 \times 22$

$\sf circumference = 88$

$\sf{\bold{\orange{\boxed{circumference = 88cm}}}}$