What is the surface area of this cylindrical cardboard? * 3.14 * 2+31.4 * 30 = 31.4+942 = 973.4 square centimeters.
2) On the map with the scale of 1: 3000000, the distance between Party A and Party B is 6CM.
The actual distance between Party A and Party B is 6 ÷1/3000000 =18000000 cm or 180 km.
It takes three hours for a car to travel from home to B. The average speed of these two cars is 180÷3=60 km/h.
3) The printing house subscribes exercise books with a batch of paper. If each book has 50 pages, it can be bound 1200. If each book has 30 pages, it can bind a book 30a=50* 1200 ∴a=2000.
You can bind 2000 more copies.
4) The front wheel of the road roller is a cylinder with a wheel width of 2M and a diameter of1.2m. The front wheel rotates six times per minute, and the road pressing area of the road roller per minute is:1.2 * 2 * 6 =14.4m. 。
5) We have a cuboid children's swimming pool, which is 25M long, 12.5M wide and 1 deep. 2M, if the swimming pool is filled with water through a water inlet pipe with a diameter of 24CM, and the water flow speed is calculated as per minute 100M, a pool of water needs to be filled: [25 *12.5 *1] ⊙ [(0.24 ÷ 2)? * 3.14 *100] = 312.5÷ 4.5416 = 6.9 points.