Question

Area of a circle is 80 cm². Work out the circumference of the circle.

Answer 1

Answer:

The circumference of circle is: 31.714 cm

Step-by-step explanation:

Let C be the circumference of the circle

And A be the area of circle

It is given that:

$A = 80cm^2$

We have to find the radius first so that it can be used to find the circumference

The area of circle is given by the formula:

$A = \pi r^2$

Putting the value of area

$80 = 3.14 * r^2\\\frac{80}{3.14} = r^2\\r^2 = 25.477$

Taking square root on both sides

$\sqrt{r^2} = \sqrt{25.477..}\\r = 5.0475\ cm$

Now

$C = 2\pi r$

Putting the value of radius

$C = 2 * 3.14 * 5.05\\C = 31.714\ cm$

Hence,

The circumference of circle is: 31.714 cm