To find the volume of a triangular prism, multiply the base area by the length of the prism. You need to know the base area and the length of the prism. Use a ruler, a pen, a divider, a piece of paper and a calculator.
- Measure the prism
Locate the base of the prism which is a triangle in this case. Stretch the divider, and measure base length of the triangle. Transfer the divider to the ruler, and read the measurement. Record it on the piece of paper. Do the same to find the height of the triangle and the length of the prism. You can use the Pythagorean theorem to get the dimensions of the prism base if it is a right triangle.
- Calculate the base area of the prism
Multiply the base length of the triangle by its height. Divide the product by two to get the area of the triangle. The area of the triangle is the base area of the prism in question.
- Calculate the volume of the prism
Multiply the base area of the prism by the length of the prism to get the volume of the prism. The volume is always in cubic units.