Forty-Four Solutions to the World's Hardest Easy Geometry Problem

This book includes 44 solutions to a famous geometry problem − Langley’s problem.

Among all these solutions, there are many wonderful and versatile ideas. The geometric proofing techniques involved includes but not limited to: congruent, similar triangles, rotation, translation, and symmetry skills; constructing equilateral triangles, circles, parallelograms, the angle bisectors, the altitudes; using incenter, circumcenter, centroid, and orthocenter; observing cyclic, collinear, and concurrent properties, and employing the trigonometric knowledge of law of sine and cosine and Ceva’s theorem with angles.

Working through these solutions is a good way to learn geometric proof skills. Each chapter includes some practice problems with the solutions to practice the skill used in that chapter. The author believes that after studying these solutions thoroughly, one can improve his/her geometry proofing skills dramatically.