Answer:
Let's call the length of the pool L, the width of the pool W, and the height of the water in the pool h. We know that the volume of the water in the pool is 720 m³. We can use this information to set up an equation:
Volume of water = L × W × h = 720 m³
We want to solve for the length of the water, L. We can rearrange the equation to solve for L:
L = 720 m³ / (W × h)
We need to find the value of L, so we need to know the values of W and h. Unfortunately, the problem doesn't provide us with the height of the water in the pool. Is there any more information that you can provide?