Question

Find the height of a cylinder whose radius is $7cm$ and the total surface area is $968c{m}^2$

Answer 1

Let height $=$h

Total surface area$=2\pi r(r+h)$

$r=7$cm

$\Rightarrow 968=2\times \frac{22}{7}\times 7(7+h)$

$\Rightarrow \frac{968}{44}=7+h$

$\Rightarrow h+7=22$

$\Rightarrow h=22-7$

$=15$cm.