If there are 5 squares in a box and each square has a side length of 24 m, we can calculate the area of one square.

The area of a square is determined by multiplying the length of one side by itself.

Area of one square = (side length)^2 = (24 m)^2 = 576 square meters.

Therefore, the area of one of the 5 squares is 576 square meters.