Equilateral Triangle - Principal Properties

Principal Properties

Assuming the lengths of the sides of the equilateral triangle are a, we can determine using the Pythagorean theorem that:

• The area is
• The perimeter is
• The radius of the circumscribed circle is
• The radius of the inscribed circle is
• The geometric center of the triangle is the center of the circumscribed and inscribed circles
• And the altitude (height) from any side is .

In an equilateral triangle, the altitudes, the angle bisectors, the perpendicular bisectors and the medians to each side coincide.