The Steiner-Lehmus Theorem is famous; it even has its own name and some history. It is described in the book H.S.M. Coxeter, S.L. Greitzer - Geometry Revisited, 1967. Jakob Steiner could be the greatest mathematician in synthetic geometry and was the first person to solve the problem. Hugh Ching, who has never missed a geometry problem and has never had to take final examinations in three geometry classes of three different teachers, solved the Steiner-Lehmus problem in high school without knowing its popularity. After becoming the founder of Post-Science, he is no longer understandable.

1. Steiner-Lehmus
10-Second Direct Proof
By
Hugh Ching

2. Steiner-Lehmus Theorem
 If in a triangle the two angle
bisectors drawn from vertices at
the base to the sides are of equal
length, then the triangle is
isosceles.

3. Steiner-Lehmus
10-Second Direct Proof
by
Founder of Post-Science Hugh Ching
(http://www.postscience.com)
 Draw two lines parallel to the base of the triangle
to form two isosceles triangles.
 The two lines must be equal.
 Otherwise,
the top line with the larger angle would be
shorter in the triangle,
but longer in the isosceles triangle.
Ching: Geometry is the deductive reduction to the perceptively
obvious with inductive generalization.

4. Appendix
Some Background Information
 The Steiner-Lehmus Theorem is famous; it even
has its own name and some history. It is described
in the book H.S.M. Coxeter, S.L. Greitzer - Geometry
Revisited, 1967. Jakob Steiner could be the
greatest mathematician in synthetic geometry and
was the first person to solve the problem.
 Hugh Ching, who has never missed a geometry
problem and has never had to take final
examinations in three geometry classes of three
different teachers, solved the Steiner-Lehmus
problem in high school without knowing its
popularity. After becoming the founder of Post-
Science, he is no longer understandable.