Surface Area and Volume Worksheets pdf with Answers Width: 7 cm. Height: 5 cm. As we said earlier, it is really easy to find the volume of a rectangular prism if you have the dimensions of each side. Volume of rectangular prism = 4 x 7 x 5. 4 x 7 x 5 = 140 cubic units. Check our surface area and volume worksheets and practice your mathematical skills. With our worksheets you will easily find the ...