Find the surface area of the water in the aquarium if 15 liters of water fills it by 2.5 dm.

We find the surface area of the water in the aquarium if 15 liters of water fill it by 2.5 dm3.
In order to find the area, you need to divide the volume of the aquarium by its height.
Since, in 1 l = 0.001 m ^ 3 = 1 dm ^ 3, then:
15 l = 15 * 1 dm ^ 3 = 15 dm ^ 3;
Find the surface area of the aquarium:
S = V / h = 15 dm ^ 3 / 2.5 dm = 15 / 2.5 dm ^ 2 = 15 / (5/2) dm ^ 2 = 15 * 2/5 dm ^ 2 = 15/5 * 2 dm ^ 2 = 3 * 2 dm ^ 2 = 6 dm ^ 2.
This means that the surface area of the aquarium is S = 6 dm ^ 2.
Answer: S = 6 dm ^ 2.