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.