Perimeter of a triangle

The perimeter of a triangle is the sum of all three sides. Denote the lengths of the three sides as a, b, c. Then the perimeter of the triangle, denoted by o, is equal to

$$\Large o = a + b + c$$

Alternatively, for the triangle ABC

$$\Large o = |AB| + |BC| + |CA|$$

where |AB| is the length of the side AB. The following triangle has side lengths equal to a = 3, b = 5, c = 4, so the circumference of the circle will be equal to

$$\Large o = 3 + 5 + 4 = 12$$