How do you find the perimeter of a triangle?

To find the perimeter of a triangle, use the equation P=A+B+C, where P is the perimeter and A, B and C are the lengths of each of the three sides of a triangle. The perimeter of a triangle is the distance around all three sides.

1. Gather supplies

   Gather a ruler, a piece of paper and a writing utensil. A calculator may be useful to complete the equation.

2. Measure the sides of the triangle

   Measure the sides of the triangle using the ruler. Write down the length of each of the sides of the triangle on a piece of paper. The first side of the triangle is considered the A side, the second side of the triangle is considered the B side and the third or longest side of the triangle is known as the C side of the triangle.

3. Calculate the perimeter

   Write down the original equation of p=a+b+c on a piece of paper. Replace A with the measured length of the A side of the triangle. Replace B with the measured length of the B side of the triangle. Replace C with the value found in measuring the C side of the triangle. Add the three values together. This is the perimeter of the triangle.