Question

A total of $35$ pen stands is to be made using cardboard in a competition each pen stand has to be of a cylinder of radius $3cm$ and height $10.5cm.$ Find the total area of cardboard required [Take $\pi =\frac{22}{7}]$

Answer 1

Given: Radius of cylinder $=3cm$

height of cylinder $=10.5cm$

Curved surface area of cylinder + Base area of cylinder $=\pi r(r+2h)$

$=\frac{22}{7}\times 3(3+2\times 10.5)$

$=\frac{1584}{7}c{m}^2$

for $1$ cylinder stand, cardboard sheet require $=$ Curved surface area of $1$ cylinder $+$ base area of cylinder

$=\frac{1584}{7}c{m}^2$

Therefore, for $35$ stands, total area of cardboard required $=35\times \frac{1584}{7}=7920c{m}^2$