Section – III

50. A rectangular piece of paper is 22 cm. long and 10 cm. wide. A cylinder is formed by rolling the paper along its length. Find the volume of the cylinder.

A. 175 cm³

B. 180 cm³

C. 185 cm³

D. None of the above

Solution:

When the paper is rolled along its length, the circumference of the cylinder formed is equal to the length and the height is equal to the breadth of the rectangle.

Let the radius and the height of the cylinder formed be r cm and h cm respectively.

2pr = 22 and h = 10

\ r = = and h = 10.

\ Volume = pr²h - or 385 cm³. Choice (D)