Two simple math problems

1 A 4-meter-long cubic water tank is filled with water. If the water in this tank is poured into another rectangular water tank with a length of 8 decimeters and a width of 25 centimeters, the water depth is 32 decimeters.

2 Make a cylindrical iron drum without a cover, with a height of 0.5 meters and a bottom diameter of 0.4 meters, and at least 0.628㎡ of iron is needed. This bucket can hold 62.8 liters of water.