As shown in the figure BD = 2cm, AC = 20cm, rotate triangle ABC around AC axis to get a figure, and calculate the volume of the figure

13 × 3.14 × 22 × 20, = 13 × 3.14 × 4 × 20, = 125615 (cubic centimeter). A: the volume of this figure is 125615 cubic centimeter

As shown in the figure, in the known triangle ABC, AC = 4, BC = 3, ab = 5?
Tomorrow's intersection ~ as shown in the figure, known triangle ABC, AC = 4, BC = 3, ab = 5!

This is a process of rotation along the right side AC of the right triangle ABC, and the solid figure obtained is a cone
The volume is 3 ^ 2 π * 4 / 3 = 12 π

In RT triangle ABC, AC = 3cm, BC = 4 CM.AB=5CM , respectively AC.BC.AB The line segment of the three sides is the axis of rotation, and three geometric bodies are obtained after one revolution
What's the relationship between these three geometries

With AC as the axis, a cone with a bottom radius of 3 and a height of 4 can be obtained; volume = π * 3 * 3 * 4 / 3 = 12 π cubic centimeter;
With BC as the axis, a cone with a bottom radius of 4 and a height of 3 can be obtained; volume = π * 4 * 4 * 3 / 3 = 16 π cubic centimeter;
With ab as the axis rotation, two conies with the bottom radius of 12 / 5 and the height sum of conies of 5 can be obtained, then the geometric volume = π * (12 / 5) & sup2; * 5 / 3 = 48 π / 5;
That is, it is equivalent to ab '< AC < BC' (AC 'represents the volume of the cube with axis rotation)

As shown in the figure BD = 2cm, AC = 20cm, rotate triangle ABC around AC axis to get a figure, and calculate the volume of the figure