Question

In a cylinder, radius is doubled and height is halved, curved surface area will be ______.

Options

• halved

• doubled

• same

• four time

Answer 1

In a cylinder, radius is doubled and height is halved, curved surface area will be same.

Explanation:

Let the radius of a cylinder be r unit and height be h unit.

Now, radius is doubled that is 2r and height is halved that is `h/2`.

Now curved surface area of a cylinder is `2 xx pi xx r xx h`

And according to the above condition,

Curved surface area = `2 xx pi xx 2 xx r xx h/2`

= `2 xx pi xx r xx h`

This is same as the curved surface area of the cylinder with radius r and height h.

Hence, the curved surface area will be same.