Illustration used to prove that triangle EFD is equilateral given that triangle ABC is equilateral and…

Illustration showing that if two angles of a triangle are equal, the bisectors of these angles are equal.

Illustration showing that can be used to prove that the base angles of an isosceles triangle are equal.

Illustration showing that if equal segments measured from the vertex are laid off on the arms of an…

Illustration showing that if equal segments prolonged through the vertex are laid off on the arms of…

Illustration showing that if equal segments measured from the end of the base are laid off on the base…

Illustration showing that if equal segments measured from the end of the base prolonged are laid off…