What are respectively the curved surface area and volume of a hemisphere of radius 21 cm? (Take $$\pi = \frac{22}{7}$$)

the curved surface area of a hemisphere = $$2\times\ \pi\ \times\ \left(radius\right)^2$$

= $$2\times\frac{22}{7}\times\left(21\right)^2$$

= $$\frac{44}{7}\times441$$

= $$44\times63$$

= 2772 $$cm^2$$

the volume of a hemisphere = $$\frac{2}{3}\times\ \pi\ \times\ \left(radius\right)^3$$

= $$\frac{2}{3}\times\frac{22}{7}\times\ \left(21\right)^3$$

= $$\frac{44}{21}\times\ \left(21\right)^3$$

= $$44\times\ \left(21\right)^2$$

= $$44\times441$$

= 19404 $$cm^3$$