Question

the area of circle is 38.5 square metre find its circumference in centimetre ​

Answer 1

Answer:

πr^2 = 38.5

r^2 = 38.5/Pi

r =38.5/r Pi

Circumference=2πr

= 2π*38.5 /rpi

=77/r

Answer 2

SOLUTION:-

Given:

•The area of the circle is 38.5m².

To find:

The circumference of the circle in cm.

Explanation:

We know that, area of circle: πr²

We know that, 1m= 100cm

So,

=) 38.5m = [38.5 × 100]cm

=) 3850cm

Area of the circle:

$= > \pi \: {r}^{2} = 3850 {cm}^{2} \\ \\ = > \frac{22}{7} \times {r}^{2} = 3850 {cm}^{2} \\ \\ = > {r}^{2} = \frac{3850 \times 7}{22} \\ \\ = > {r}^{2} = 175 \times 7 \\ \\ = > {r}^{2} = 1225 \\ \\ = > r = \sqrt{1225} \\ \\ = > r = 35cm$

Now,

Circumference of the circle: 2πr

$= > 2 \times \frac{22}{7} \times 35 \\ \\ = > \frac{44}{7} \times 35 \\ \\ = >(44 \times 5)cm \\ \\ = > 220cm$

Thus,

The circumference of the circle is 220cm.