To find the amount of space the cage occupies, you need to find the volume of the page. To do this, multiply the edge length (18 units) by itself three times.
Volume = 18 x 18 x 18 = 5832
So, the volume of the cage is 5832 units.
Note: Multiplying 18 by itself three times is the same thing as "cubing" the number.
18^3 = 5832
Hope that helps!!