Erdös-Mordell Theorem

If is any point inside a Triangle , and , , and are the feet of the perpendiculars from upon the respective sides , , and , then

References

Bankoff, L. ``An Elementary Proof of the Erdös-Mordell Theorem.'' Amer. Math. Monthly 65, 521, 1958.

Brabant, H. ``The Erdös-Mordell Inequality Again.'' Nieuw Tijdschr. Wisk. 46, 87, 1958/1959.

Casey, J. A Sequel to the First Six Books of the Elements of Euclid, 6th ed. Dublin: Hodges, Figgis, & Co., p. 253, 1892.

Coxeter, H. S. M. Introduction to Geometry, 2nd ed. New York: Wiley, p. 9, 1969.

Erdös, P. ``Problem 3740.'' Amer. Math. Monthly 42, 396, 1935.

Fejes-Tóth, L. Lagerungen in der Ebene auf der Kugel und im Raum. Berlin: Springer, 1953.

Mordell, L. J. ``On Geometric Problems of Erdös and Oppenheim.'' Math. Gaz. 46, 213-215, 1962.

Mordell, L. J. and Barrow, D. F. ``Solution to Problem 3740.'' Amer. Math. Monthly 44, 252-254, 1937.

Oppenheim, A. ``The Erdös Inequality and Other Inequalities for a Triangle.'' Amer. Math. Monthly 68, 226-230 and 349, 1961.

Veldkamp, G. R. ``The Erdös-Mordell Inequality.'' Nieuw Tijdschr. Wisk. 45, 193-196, 1957/1958.

• Curve of Constant Precession
• Curve of Constant Slope
• Curve of Constant Width
• Curvilinear Coordinates
• Cushion
• Cusp
• Cusp Catastrophe
• Cusp Form
• Cusp Map
• Cusp Point
• Cutting
• Cut-Vertex
• CW-Approximation Theorem
• CW-Complex
• Transfinite Diameter
• Transfinite Number
• Transform
• Transformation
• Transitive
• Transitive Closure
• Transitive Reduction
• Transitivity Class
• Translation
• Translation Relation
• Transpose