1, a cylindrical container with a bottom diameter of 20 cm and a part of water. There is a cone plumb hammer in the water, with the bottom diameter 12 cm and the height 10 cm. How many centimeters did the water in the container drop when the plumb hammer was taken out of the water?

2. The side area of the cylinder is 150 cm2, and the radius of the bottom surface is 4 cm. How many cubic centimeters is its volume?

The height of triangle ABC is 2cm, and the bottom is 20cm. Rotate the triangle ABC around AC to get a figure, and find the volume of this figure. (π is about equal to 3) Tip: The rotating figure is two cones.

π is PAI

1:

V-cone = pai (6 2) *10/3 =120 * pai.

S- bottom cylinder = pai (102) =100 * pai.

V-cone /S bottom column = h =120 * pai/(100 * pai) =1.2cm.

2:

C bottom =2*PAI*r=8*PAI

H cylinder = 150/(8 * rows)

S bottom == 16*PAI

V cylinder =S bottom *H cylinder =150/(8 * pai) *16 * pai = 300 cm 3.

3:

=PAI*R^2*H=20*20*PAI*2=800*PAI

Because PAI=3, it = 2400 cm 3.