A triangle is a three-sided polygon, existing in various lengths and forms. To calculate square footage of a triangular shape, you need to calculate the area of the triangle with feet as the unit of measurement.

### Measure the length of the base and the height

Measure the length of the base and the height of the triangle. The base can be any side, but make sure it is consistent throughout the entire process. The height of the triangle is simply the distance from the opposite corner to the base. When measuring height, your measurement should be at a 90-degree angle from the base. Also ensure that you are measuring in feet. This guarantees that your area ends up being measured in square footage.

### Plug the variables into the equation

The equation for calculating the area of a triangle is ½ multiplied by the base multiplied by the height. Take the base and height measurements in Step 1 and multiply them together, and then divide the product of these measurements by 2.

### Solve the equation

Do the math and solve the equation. If you perform this calculation correctly, you should have the square footage of your triangle. To check your work, divide your answer by two variables. If your answer was correct, this number should be your third variable.