Question 949772
A water reservoir is shaped like a rectangular solid with a base that is 50 yards by 30 yards, and a vertical height of 20 yards. At the start of a three month period of no rain, the reservoir was completely full. At the end of this period, the height of the water was down to 6 yards. How much water was used in the three month period? 
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The volume is the product of the 3 dimensions.
The depth changed by 14 yards. ("down to 6" from 20)
Vol used = 50*30*14 = 21000 cubic yards