Relation between the inradius and exradii of an equilateral triangle


an equilateral triangle is a triangle in which all three sides are equal. In traditional or Euclidean geometry, equilateral triangles are also equiangular; that is, all three internal angles are also congruent to each other and are each 60°. The radius of the inscribed circle of the triangle is related to the extraradii of the triangle. ( An excircle of the triangle is a circle lying outside the triangle, tangent to one of its sides and tangent to the extensions of the other two. Their radii are called exradii.)

Related formulas


rThe inradius of the triangle (m)
raThe exradius of the triangle (m)
rbThe exradius of the triangle (m)
rcThe exradius of the triangle (m)