A cuboid fish tank is nine tenths of a meter long and four fifths of a meter wide. It contains nine fifths of a cubic meter of water. How deep is it?

A cuboid fish tank is nine tenths of a meter long and four fifths of a meter wide. It contains nine fifths of a cubic meter of water. How deep is it?

Its length is 0.9 meters, width is 0.8 meters, bottom area is 0.72 square meters, 9 / 25 is equal to 0.36 cubic meters, 0.36 divided by 0.72 is equal to 0.5 meters, that is, the water depth is 0.5 meters

A cuboid fish tank is 9 / 10 long and 4 / 5 wide. It contains 9 / 25 cubic meters of water. How deep is it?

10 △ 5 × 4 = 8 (m)
10 △ 10 × 9 = 9 (m)
1000 △ 25 × 9 = 360 (M3)
8 × 9 = 63 (M2)
360 △ 63 = (m)

A cuboid fish tank, measured from the inside, is 6 decimeters long and 4 decimeters wide. The original water is four fifths of the capacity of the tank. Now we need to add water to the tank
5 / 6 of capacity, how many kg of water do you need? (1 kg per liter)

Water needs to be added
6×4×5×（5/6-4/5）×1
=120×1/30
=4 (kg)