How to Find the Cubic Feet of a Triangle

Finding the area of a geometric object is an essential part practical mathematics. By understanding the principles involved in calculating the square feet of rectangles and squares, you can determine the area of a triangle as well.

Things You'll Need

• Ruler
• Paper
• Pencil
• Calculator

Instructions

1. 

   Know how to determine the area of a rectangle. To determine the area of a rectangle in square feet, simply measure the width and length and multiply together. In the image, the two sides are labeled "A" and "B."

2. 

   When you are determining the area of a "right" triangle, simply follow Step 1, using the two sides of the triangle that form the right angle, and then divide the result in two. The answer is the area of a right triangle. Curious how that works? Look at the diagram. The area shaded in gray is the triangle, the unfilled area is a rectangle made up of two identical right triangles sharing the hypotenuse. As you can see, multiplying sides A and B together will come up with the area for the entire figure. The triangle is only half of that.

3. 

   Add another step if your triangle is not a right triangle. First, divide the triangle into two right triangles. In the diagram, the line marked "A" is the one I added to make two right triangles out of one triangle. Then multiply A and B for the first triangle, and divide by two. Repeat the process for the second triangle, then add the two results together. You'll have the area of the triangle.

Tips & Warnings

• If you need to measure in inches, simply divide your results by 1,728 to yield square feet.