The students made 20 cylindrical lampshades with colored paper. Each lampshade is 35CM high and the circumference of the bottom ring is 47? 1 cm. How much colored paper do you need at least?

3. (Cuboid) is 8.5dm long, 3dm high, 4dm wide (cylinder) with a base diameter of 8cm, 5cm high (cone) with a base diameter 15cm and 8cm high.

4. How many cubic centimeters of coal does a piece of honeycomb coal need? (Keep integers as numbers) 9cm high, 2cm hole diameter, 12 cm coal diameter, 12 hole.

5 Tapered sand pile, with a bottom area of 28.26 square meters and a height of 2.5 meters ... How many meters can you pave a 2cm thick road surface with this pile of sand on a 10m wide road surface?

There is a wooden cube, and its side length is 4dm. Make this piece of wood into the largest cylinder. What is the volume of this cylinder?