Container W and X are identical containers with the same base area and height. Container W is filled to the brim with water while Container X is empty. After 261 cm³ of water from Container W is poured into Container X, the depth of water in Container X is ¹₆ the depth of water in Container W. If the height of Container X is 21 cm, what is the base area of Container X?
The depth of water is proportional to the volume of water.

After water from Container W is poured into Container X:

Volume of water in Container W : Volume of water in Container X
 6 : 1

1 u = 261

Total volume of Container X
= 6 u + 1 u
= 7 u
= 7 x 261
= 1827 cm³

Base area of Container X
= 1827 ÷ 21
= 87 cm²

Answer(s): 87 cm²