What is the volume of a right pyramid whose base is a square with a side 6 m long and whose altitude is equal to the base side?

The answer is still:

Volume pyramid = 1/3 x base_area x height

= 1/3 x (6m x 6m) x 6m

= 72m3.

V(pyramid) = (1/3)Bh, where B is the area of the base.

V = (1/3)(6^2)(6) = 72 m^3