Volume of the prism: V=B×H Base of the prism is a trapezoid, so the volume equation will be: V=((a+b)/2)×h×H Information that is given: h=7 inches(height of the base); x=5 inches(segment of a side of the trapezoid); H=4 inches(height of the prism); b=8 inches(shorter side of the trapezoid). Calculate the longer side of the trapezoid: a=2x+b a=2×5+8=10+8=18 in. Now you can calculate the base: B=((a+b)/2)×h B=((18+8)/2)×7 B=91 in. Volume of the prism: V=91 × 4 V=364 inches.