Finding the perimeter of a triangle is a relatively straightforward process using a formula similar to finding the perimeter of a rectangle. In the simplest terms, you are finding the length of all the outer sides and adding them together. The perimeter is the continuous line forming the boundary of a closed geometric figure such as a triangle.

## Instructions for finding the perimeter of a triangle

The perimeter of a triangle is found by *adding the length of all three sides of the triangle*.

**The formula**

P = a + b + c

**An example of finding the perimeter of a triangle using “in” for inches as the measure for each side**

*a* = 2 in

*b* = 2 in

*c* = 3 in

P = 2 in + 2 in + 3 in = 7 in

The perimeter of the triangle in this example is seven (7) inches using the formula.

**All posts in this series:** What is a circle? | What is the radius of a circle? | What is the diameter of a circle? | What is the circumference of a circle? | What is the area of a rectangle? | What is the perimeter of a triangle? | What is the area of a triangle?