Two square pyramids have the same volume. for the first pyramid, the side length of the base is 20 in. and the height is 21 in. the second pyramid has a height of 84 in. what is the side length of the base of the second pyramid?

The volume of the pyramid is calculated by multiplying the area of the base by the height of the figure. For this item, for the figures to have the same volume,
                          V = B1H1 = B2H2
Then, we substitute the given values, and since we are not given the shape of the base and the volume of the entire figure, we can just solve it through the way below.
                        (20 in)(21 in) = (x in)(84 in)
The value of x in the problem is 5 inches.