Prism volume = width*length*height
56 1/4 = 3 3/4 * 7 1/2 * h
56.25=3.75*7.5*h
h=(56.25)/(3.75*7.5)=2
So that the missing dimension (height) is 2 ft
56 1/4 = 3 3/4 * 7 1/2 * h
56.25=3.75*7.5*h
h=(56.25)/(3.75*7.5)=2
So that the missing dimension (height) is 2 ft