Question

50 circular plates each of diameter 14 cm and thickness 0.5 cm are placed one above the other to form a right circular cylinder. Find its total surface area.

Answer 1

Radius of the cylinder = Radius of the plate = 7 cm

Height of the cylinder = No. of plates $\times$ Thickness of each plate = 50 $\times$ 0.5 = 25 cm

So, total surface area $=2\pi r(r+h)=2\times \frac{22}{7}\times 7\times (7+25)$

$=2\times \frac{22}{7}\times 7\times 32=1408c{m}^2$