Question

The circumference of a circle is $22cm$. Find its area? And also find the area of the semicircle

Answer 1

Let the radius of the circle be $rcm$
Then circumference $=2\pi r$
$\therefore 2\pi r=22$
$2\times \times r=22$
$r=22\times =3.5cm$
$\therefore$ Radius of the circle $=3.5cm$
Area of the circle $\pi r^2=(\frac{22}{7}\times \frac{7}{2}\times \frac{7}{2})c{m}^2$
$=38.5c{m}^2$
Area of the semi circle $=\frac{1}{2}\pi r^2$
$=\frac{1}{2}\times 38.5=19.25c{m}^2$