Question

the ratio of circumference and area of a circle is 2 is 27 find its circumference

Answer 1

We know that circumference of a circle = 2πr

Area of circle = πr²

So we are given that their ratio = 2 : 27

Hence,
$\frac{2\pi r}{\pi {r}^{2} } = \frac{2}{27}$
Cancel π and r

=>
$\frac{2}{r} = \frac{2}{27} \\ \\ = > 2r = 27 \times 2 \\ \\ = > r = \frac{27 \times 2}{2} \\ \\ = > r = 27$


Now since r = 27 units,

circumference = 2πr = 2 × 22/7 × 27

=> circumference = 1188/7 units.


Or, 169.71 units (approx)

Answer 2

Solution:-
$<b>$
$= > \frac{2\pi \: r}{\pi {r}^{2} } = \frac{2}{27} \\ \\ \\ = > \frac{2}{r} = \frac{2}{27} \\ \\ = > r = 27$

Radius = 27 units.

$= > circumference = 2\pi \: r \\ \\ = > 2 \times \frac{22}{7} \times 27 \\ \\ = > 169.71 units$