1. A rectangular piece of paper, 25cm long and15cm wide. Roll this rectangular paper roll into a cylindrical paper tube (excluding the joint). What is the height of the cylindrical paper tube? What are the perimeters of the ground and the bottom?

The height may be 25 cm and the perimeter of the bottom surface is 15 cm.

Or the height may be 15cm, and the perimeter of the bottom surface is 25cm.

2. Coke cans are cylindrical, with a bottom diameter of 7 cm and a height of 12 cm. Put 24 cans of coke in a box (the coke in the box in the picture is 6 cans long and 4 cans wide, making a total of 24 cans). How many centimeters is the length, width and height of this box?

Length: 7× 6 = 42 cm

Width: 7× 4 = 28 cm

Height:12cm

3. A cylindrical pool, the inner and outer walls and the bottom of the pool should be inlaid with tiles. The diameter of the bottom of the pool is 6m, the depth of the pool is1.2m. How many square centimeters is the tiled area?

Bottom area+side area = tile area.

3.14× (6÷ 2) 2+3.14× 6×1.2 = 50.868 (square meter) = 508680 (square centimeter).