Diagonal of the axial section of the cylinder 35 cm height 21. find the radius of the cylinder.

The diagonal of the axial section of the cylinder, its height and base diameter is a right-angled triangle.

The legs of this triangle are the diameter of the base and the height of the cylinder, the hypotenuse is the diagonal of the axial section.

Let’s say that the base diameter is x cm.

By the Pythagorean theorem, we can compose the following equation:

21² + x² = 35²,

441 + x² = 1225,

x² = 784,

x = 28.

Since the diameter of the base of the cylinder is 28, its radius is:

28: 2 = 14 cm.

Answer: 14 cm.