Question

A solid metallic cylinder of radius $12cm$ and height $175cm$ is melted and moulded into another solid cylinder of height $63cm$. What is the radius of the new cylinder?

• A. $14$
• B. $4\pi$
• C. $20$
• D. $5\pi$

Answer 1

The correct option is C $20$

Radius of cylinder $=12cm$
Height $=175cm$
Height of new cylinder $=63cm$
Let the radius of New cylinder $r$
So, volume of both cylinder should be equal $\pi {\left(12\right)}^{2}175=\pi r^2\left(63\right)$
On solving $r=20cm$