Question

When the figure given above is spun around its vertical axis, the volume of the solid formed will be:

• A. $9\pi$
• B. $36\pi$
• C. $72\pi$
• D. $144\pi$
• E. $288\pi$

Answer 1

Answer: (D)

$144\pi$

The solid formed after spin will be a Hemisphere whose radius is $6$ cm.

Volume of hemisphere $=$ $\frac{2}{3}\pi r^3$

$\therefore$ volume $=\frac{2}{3}\pi \times 6^3$

$=\frac{2}{3}\pi \times 6\times 6\times 6=144\pi$