What is the maximum volume of a square pyramid that can fit inside a cube with a side length of 18cm?

The base of the square pyramid must be a square with a side length of 18 cm, which means its area is 18 x 18 = 324 square cm.

The height of the pyramid can be found using the Pythagorean theorem:

h^2 = (18/2)^2 + (18/2)^2

h^2 = 9^2 + 9^2

h^2 = 162

h = √162 ≈ 12.73 cm

The volume of the pyramid is:

V = (1/3) x base area x height

V = (1/3) x 324 x 12.73

V ≈ 1,730.48 cubic cm

Therefore, the maximum volume of a square pyramid that can fit inside a cube with a side length of 18 cm is approximately 1,730.48 cubic cm.