Question

find the area and perimeter of the circle whose radius is 21 CM

Answer 1

Perimeter of a circle means its circumference.

Formula for circumference is 2πr

So here perimeter is 2×3.14×21= 131.88cm

Now for area the formula is
$\pi {r}^{2}$
So here area becomes.
$= \pi {21 }^{2} \\ \\ = 1384.74cm^2$

Answer 2

Answer

Area

= 22÷7×21 × 21

66 ×21= 1386