A rectangular sheet of paper 40cm x 22cm, is rolled to form a hollow cylinder ofheight 40cm. The radius of the cylinder(in cm) is

To find the radius of the cylinder, we need to use the formula for the surface area of a cylinder. The surface area of a cylinder is given by the formula:

Surface Area = 2πrh + 2πr^2

In this case, we know that the height of the cylinder is 40cm. We also know that the rectangular sheet of paper, when rolled, forms the lateral surface of the cylinder. The length of the rectangular sheet is equal to the circumference of the base of the cylinder, which is 2πr.

So, the length of the rectangular sheet is 2πr = 40cm.

To find the radius, we can rearrange the equation to solve for r:

r = (40cm) / (2π)

Now, we can calculate the value of r using a calculator:

r ≈ 6.37 cm

Therefore, the radius of the cylinder is approximately 6.37 cm.