The height of a cylinder is equal to that of a cone. The bottom radius of the cylinder is one fourth of that of the cone. What is the volume of the cylinder equivalent to that of the cone?

The height of a cylinder is equal to that of a cone. The bottom radius of the cylinder is one fourth of that of the cone. What is the volume of the cylinder equivalent to that of the cone?

Cylinder bottom radius: cone bottom radius = 1:4
Area of cylinder bottom: area of cone bottom = 1 × 1:4 × 4 = 1:16
Cylinder height: cone height = 1:1
Cylinder volume: cone volume = 1 × 1:16 × 1 × 1 / 3 = 3:16
The volume of a cylinder is equal to 3 / 16 = 3 / 16 of a cone

The base radius of a cylinder is half of that of a cone, and their heights are equal. The volume of a cone is a fraction of that of a cylinder

For 14 seconds,
The bottom area of a cylinder is 1 / 2 × 1 / 2 = 1 / 4 of that of a cone
The volume of a cone is the volume of a cylinder: (1 × 1 × 1 / 3) / (1 / 4 × 1) = 4 / 3

When the diameter of a circle is reduced to 13, its perimeter and area are also reduced to 13______ (judge right or wrong)

If the diameter of a circle is reduced to the original 13, its radius is also reduced to the original 13, then its perimeter is reduced to the original 13, and its area is reduced to the original 19