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First: a cone, the volume is 480 cubic centimeters, the height is 20 centimeters. How many square centimeters is its bottom area? The second way: a pile of coal is transported into the school canteen and piled into an approximate cone. Its bottom diameter is 8 meters and its height is 1.2 meters. How many cubic meters of coal is there? The third course: there is a gravel pile which is similar to a cone. The perimeter of its bottom surface is 18.84 meters and the height is 8 meters. How many meters can you lay on a 10 meter wide road with this pile of gravel 10 cm thick?
1. V = 1 / 3SH s = 3V / h = 3 * 480 cubic centimeter / 20 centimeter = 72 square centimeter answer: its bottom area is 72 square centimeter 2, v = 1 / 3 * sh = 1 / 3 * 3.14 * (8 / 2) & 710; 2 * 1.2 = 20.096 cubic meter answer: this pile of coal has 20.096 cubic meter 3, C = 2 π r r = C / 2 π = 18.84 / (2 * 3.14) = 3 meters, v = 1 / 3
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