8*2= 16 (cm)
16 *16 * 4+8 * 25 * 2 =1424 (square centimeter)
A: At least 1424 square centimeters of hard paper is required.
Conical sand pile with a bottom area of 12.56 square meters and a height of 1.2 meters. If this pile of sand is used, the road surface 10 meter wide and the sand is 0.2 meter thick. How many meters can you spread?
12.56 *1.2 *1/3 = 5.024 (m3)
5.024/(10 * 0.2) = 2.512 (m)
Answer: it can be 2.5 12 meters long.
Put a piece of bronze (completely immersed in water) into a square glass tank with a bottom length of 2 decimeters, and the water level will rise 1 decimeter (ignoring the glass thickness).
(1) What is the volume of this bronze?
2*2* 1=4 (cubic decimeter)
The volume of this bronze is 4 cubic decimeters.
(2) If there is no cubic decimeter bronze weighing 8.5 kilograms, how many kilograms does this bronze weigh?
4*8.5=34 (kg)
A: This bronze medal weighs 34 kilograms.
(3) This bronze ware is made of copper, tin and zinc in the ratio of 30:3: 1. How many kilograms of copper, tin and zinc does this bronze ware contain?
30+3+ 1=34
Copper: 34*30/34=30 (kg)
Tin: 34*3/34=3 (kg)
Zinc: 34* 1/34= 1 (kg)
Answer: 30 kg of copper, 3 kg of tin and zinc 1 kg.
(4) If this bronze ware is made into a cylinder with a base diameter of10cm, what is its height? (Keep integer)
10/2=5 (cm)
5*5*3. 14=78.5 (square centimeter)
4 cubic decimeters =4000 cubic centimeters
4000/78.5 is about 50 (cm).
A: Its height is 50 centimeters.