Question

The area of a circle is 15400 m sq. find its circumference.

Answer 1

area of circle=πr²
15400=πr²
r²=15400×7/22
r²=4900
r=70m²
circumference=2πr
=2×22/7×70
=440m²

Answer 2

Given,

The area of a circle is 15400 m sq.

To Find,

Its circumference =?

Solution,

We can find the circumference as follows:

It is given to us that the area of a circle is 15400 m sq. To find the circumference, we will first find the radius of the circle.

We know that the area of a circle is given as:

$Area\: of\: a\: circle = \pi r^{2}$

Where, $r = radius$

Substituting the values and taking $\pi = \frac{22}{7}$,

$15400 = \frac{22}{7} *r^{2}$

$15400*\frac{7}{22} = r^{2}$

$4900 = r^{2}$

$r = \sqrt{4900} = 70\: m$

Therefore, the radius of the circle is 70 m.

Now,

The circumference of a circle is given as:

$Circumference = 2\pi r$

Substituting the values,

$Circumference = 2*\frac{22}{7} *70$

                          $= 440\: m$

Hence, the circumference of the circle is 400 m.