Equilateral Triangle Formulas

Posted In: Mathematics

An equilateral triangle is a triangle in which all three sides are equal. In the familiar Euclidean geometry, equilateral triangles are also equiangular; that is, all three internal angles are also congruent to each other and are each 60°.

Equilateral Triangle

Side of a equilateral triangle: a
Altitude: h
Radius of circumscribed circle: R
Radius of inscribed circle: r
Perimeter: L
Area: S

  1. $h={a√3}/2$
  2. $R=2/3h={a√3}/3$
  3. $r=1/3h={a√3}/6=R/2$
  4. $L=3a$
  5. $S={ah}/2={a^2\ √3}/4$

Post Tags: Geometry


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