Question

The circumfrence of a circle is 3.14 cm . Find the radius and area of circle.
​

Answer 1

Given :

⬤ Circumference of Circle is 3.14 cm .

To Find :

⬤ Radius of Circle .

⬤ Area of Circle .

Formula Used :

$\bf[\:{Circumference\:of\: Circle = 2\pi{r}}\:]$

• r = radius

Solution :

According to the Formula :-

3.14 = 2πr

3.14 = 2 × 22/7 × r

314/100 = 44r/7

By Cross Multiplication :-

r = 314 × 7/100 × 44

r = 2198/4400

r = 0.4

Therefore , The Radius of Circle is 0.4 cm .

Formula Used :

$\bf[\:{Area\:of\:Circle=\pi{r}^{2}}\:]$

• r = radius

Now :

πr²

22/7 × 0.4 × 0.4

22/7 × 04/10 × 04/10

352/700

0.5

Therefore , The Area of Circle is 0.5 cm² .

Answer 2

Given :

• Circumference of Circle is 3.14 cm .

To Find :

• Radius of Circle .

• Area of Circle .

Solution :

We know that,

$\rm\:\bigg\lgroup{Circumference\:of\: Circle = 2\pi{r}}\:\bigg\rgroup$

• r = radius

★ According to the Formula :-

$\sf{\to3.14 = 2πr }$

$\sf{\to3.14 = 2 × 22/7 × r }$

$\sf{\to314/100 = 44r/7}$

By Cross Multiplication :-

$\sf{\to \: r = 314 × 7/100 × 44}$

$\sf{\to \: r = 2198/4400}$

$\sf{\to \: r = 0.4}$

Therefore ,

• The Radius of Circle = 0.4 cm .

We know that,

$\rm\bigg\lgroup\:{Area\:of\:Circle=\pi{r}^{2}}\:\bigg\rgroup$

• r = radius

Now,

$\sf{\to22/7 × 0.4 × 0.4}$

$\sf{\to22/7 × 04/10 × 04/10 }$

$\sf{\to352/700}$

${\to{\boxed{\red{\bf0.5} }}}$

Therefore ,

• The Area of Circle = 0.5 cm² .