How many gallons does a 24 ft round pool hold if 4 deep?

```

Volume = π * radius^2 * height

```

Given that the pool is 24 feet in diameter, its radius is half of that, which is 12 feet. The height of the pool is 4 feet. Substituting these values into the formula, we get:

```

Volume = π * 12^2 * 4

Volume = π * 144 * 4

Volume = 1809.56 cubic feet

```

Now, we need to convert cubic feet to gallons. There are approximately 7.48 gallons in one cubic foot. So, multiplying the volume in cubic feet by 7.48 gives us the volume in gallons:

```

Volume in gallons = 1809.56 cubic feet * 7.48 gallons/cubic feet

Volume in gallons ≈ 13,534.96 gallons

```

Therefore, a 24 ft round pool that is 4 feet deep holds approximately 13,535 gallons of water.