To find the volume of a rectangle prism, you will need to use the formula V= lenght * width * height. Make sure you state your answer in cubic units. For example you have a rectangle prism with a lenght of 15m, width 8m, and a hieght of 12m. V = l * w * h V = 15 * 8 * 12 V= 120 * 12 V= 1,440 V= 1,440m^3