Question

A solid cylinder is cut vertically as shown in the image. Its diameter and height are $12cm$ and $15cm$, respectively. If the diameter is divided in the ratio $3:1$, what is the increase in its surface area (in $c{m}^2$)?

• A. $140\sqrt{3}$
• B. $120\sqrt{3}$
• C. $224\sqrt{3}$
• D. $180\sqrt{3}$

Answer 1

The correct option is D $180\sqrt{3}$