Question

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

Answer 1

50 circular plate

diameter of plate $=14cm$

Radius of plate = $d/2=\frac{14}{2}=7cm$

thickness $=0.5cm$

$\to$ Height of the cylinder = No. of plates $\times$ thickness of plate

$=50\times 0.5$

$=25cm$

$\to$ total surface Area = curved surface + 2 $\times$ area of base

$=2\pi r.h+2\times \pi r^2$

$=2\pi r(h+r)$

$=2\pi \times 7(25+7)$

$=2\times \frac{22}{7}\times 7\times 32$

$=1408c{m}^2$