Pyramid a is a square pyramid with a base side length of 12 inches and a height of 8 inches. pyramid b is a square pyramid with a base side length of 36 inches and a height of 24 inches. how many times bigger is the volume of pyramid b than pyramid a?

The answer is 27 times.

Va - the volume of the pyramid A
Vb - the volume of the pyramid B

The volume of the square pyramid is:
V = s² * h / 3
s - side
h - height

We know:
sa = 12 in
ha = 8 in

sb = 36 in
hb = 24 in

Va = sa² * ha / 3 = 12² * 8 / 3 = 144 * 8 / 3 = 1152/3 = 384 in²
Vb = sb² * hb / 3 = 36² * 24 / 3 = 1296 * 8 / 3 = 31104/3 = 10368 in²

We want to know how many times the volume of pyramid B is bigger than pyramid A :
Vb/Va = 10368/384 = 27