Answer:
2.36 liters
Explanation:
The volume Janet wants is 1/3 of 1/2 of the volume of a sphere with radius 15 cm. The formula for the volume of a sphere is given.
Application
The water volume is ...
V = (1/3)(1/2)(4/3π)(15 cm)³ = 750π cm³ ≈ 2356 cm³
There are 1000 cm³ in 1 liter, so Janet needs about ...
2356 cm³/(1000 cm³/L) = 2.356 L
Janet should put about 2.36 liters of water in the fish tank.