The perimeter of an equilateral triangle is the total length of its outline — the sum of all three equal sides. It is used when fencing triangular plots, framing figures, or calculating how much material is needed to border a triangular surface.

The Formula

P = 3 × t

• P — perimeter of the triangle (cm, m, etc.)
• t — length of the side (all three sides are equal)

This formula is so simple because in an equilateral triangle all three sides have exactly the same length, so multiplying one side by 3 gives the full perimeter.

Step-by-Step Example