Question

The radius of the cylinder is made twice as large. How should the height be changed, so that volume remains the same as before?

Answer 1

Let r be the radius and h be the height of the original cylinder so that $2r$ and H be that of the corresponding one
Now,

$\pi r^{2}h=\pi {\left(2r\right)}^{2}H$

$\therefore 4h=b$

or $H=\frac{1}{4}h$

=25%h

$\therefore$ Height of the new one must be 25% if the original one