Given the volume of the cylinder, the diameter and height of the cylinder are required to be equal?

Given the volume of the cylinder, the diameter and height of the cylinder are required to be equal?

Let the radius of the cylinder be r, then the height h = 2R
Volume v = π r squared H = 2 π r cubic
So r = V / 2 π under the third radical
V / 2 π under H = 2 * cubic radical

Find a cylinder with diameter of 2.5cm, height of 2m, density of 7.8, weight

M = density * V = (2.5 / 2) & sup2; π * 200 * 7.8 = 1950 π G
If you find gravity, multiply it by 10

When a cylinder with a diameter of 4cm and a height of 5cm is cut into two equal parts along the bottom diameter, the surface area is increased by () square centimeter
A. 3.14×4×5×2B. 4×5C. 4×5×2

4 × 5 × 2 = 40 (square centimeter); a: the surface area has increased by 40 square centimeter