Only the lateral area is not covered on the top and bottom of the cylindrical lampshade, and the cylindrical lateral area = the perimeter of the bottom * is high. Calculate a lateral area first, and the area of 1 lampshade is 35*47. 1= 1648.5 (square centimeter), and then multiply it by 20 such lampshades.
20 is 1648.5*20=32970 (square centimeter).
2. A conical sand pile with a bottom area of 28.26 square meters and a height of 2.5 meters. Using this pile of sand to pave a pavement with a thickness of 2cm on a pavement with a width of 10m, how many meters can it be paved?
Cone sand pile volume: 1/3× 28.26× 2.5 = 23.55 (m3) Road thickness: 2cm = 0.02m Road length: 23.55 ÷ 0.02 ÷10 =/kloc-0.
There is a cube made of wood, and its side length is 4dm. Make this piece of wood into the largest cylinder. What is the volume of this cylinder?
The bottom surface has a diameter of 4 decimeters, a radius of 2 decimeters and a height of 4 decimeters.
V = 3. 14x2x4 = 50.24 square decimeter.