The area of an equilateral triangle is the space inside its three equal sides. This formula is very useful in architecture, graphic design and surveying when working with perfectly symmetrical triangular shapes.

The Formula

A = (√3 / 4) × t²

• A — area of the triangle (cm², m², etc.)
• √3 — square root of 3, approximately 1.73205
• t — length of the side of the equilateral triangle

The constant √3/4 comes from the height of an equilateral triangle (h = t√3/2), which multiplied by the base (t) and divided by 2 gives the general area formula.

Step-by-Step Example