# What is volume?

The height of a right circular cylinder is 21cm. Its curved surface area is 924 sq cm. Then its volume is:

- 1859 cu. cm
- 1586 cu. cm
- 3234 cu. cm
- None of these

**Answer: (4) None of these**

**Explanation:-**

Let the radius of the right circular cylinder be R.

**Formula-**

The surface area of right circular cylinder = 2 π r h

Then, 2 x 22 x 21 x R/7 = 924

R = 924 x 7/44 x 21

R = 21 x 7/21

R = 7

Then, the volume of the right circular cylinder = 2 x 22 x 7 x 7 x 21/7

= 44 x 147

= 6468 cm. cm

Hence, the correct answer is option (4) None of these.