Radius of the base of a cylinder is 20 cm and its height is 13 cm. Find its curved surface area of and total surface area.
Radius of the cylinder, $$r=20\ cm$$
Height of the cylinder, $$h=13\ cm$$
$$\therefore$$ Curved surface area of the cylinder $$=2\pi rh =2\times 3.14 \times 20 \times 13$$
$$=1632.80\ cm^2$$
Also,
Total surface area of the cylinder $$=2\pi r ( r+h)$$
$$=2\times 3.14 \times 20\times (20+13) $$
$$=2 \times 3.14 \times 20\times 33=4144.80\ cm^2$$
Thus, the curved surface area and the total surface area of the cylinder is $$1632.80\ cm^2$$ and $$4144.80\ cm^2$$, respectively.