What is the perimeter formula for a triangle?

The perimeter of a triangle is calculated by summing the lengths of all three sides. The formula reflects this relationship, where each side is denoted as S1, S2, and S3. Thus, to determine the total distance around the triangle, you simply add these three values together: S1 + S2 + S3.

The other options provided relate to different geometrical calculations. One describes a triangle's area (base and height), while others reference formulas that do not apply to the perimeter of a triangle. Understanding the context of a perimeter as a linear measure that involves the edges of a shape is essential for recognizing why this summation accurately represents the perimeter of a triangle.