# A rectangle with a diagonal of 25 cm and one side 20 cm rotates around the smaller side.

**A rectangle with a diagonal of 25 cm and one side 20 cm rotates around the smaller side. Calculate: a) the length of the height of the resulting cylinder, b) the area of the base of the cylinder.**

Let’s find out how many centimeters the second side of our rectangle will correspond to, because it is a leg in a triangle, where the diagonal of the rectangle is the hypotenuse:

√25 ^ 2 – 20 ^ 2 = √625 – 400 = √225 = 15.

Let’s find out which side in the rectangle is smaller:

20> 15.

By condition, it rotates around the smaller side, which means that it will be the height of the cylinder.

Answer: 15 centimeters.

Let’s find out what the area of the base of the cylinder will be equal to (a circle with a radius equal to the length of the second side):

3.14 * 20 ^ 2 = 1256.

Answer: 1256 cm2.