AoPSWiki
Want to learn how to tackle those tough AMC/AIME/Olympiad algebra problems? Check out Art of Problem Solving's Intermediate Algebra by Richard Rusczyk and Mathew Crawford. Over 1600 problems!

Carnot's Thereom

From AoPSWiki

Revision as of 12:04, 27 August 2008 by 1=2 (Talk | contribs)
(diff) ← Older revision | Current revision (diff) | Newer revision → (diff)

Carnot's Theorem states that in a triangle ABC with A_1\in BC, B_1\in AC, and C_1\in AB, perpendiculars to the sides BC, AC, and AB at A_1, B_1, and C_1 are concurrent if and only if A_1B^2+C_1A^2+B_1C^2=A_1C^2+C_1B^2+B_1A^2.

Contents

Proof

This proof is incomplete. You can help us out by completing it.

Problems

Olympiad

\triangle ABC is a triangle. Take points D, E, F on the perpendicular bisectors of BC, CA, AB respectively. Show that the lines through A, B, C perpendicular to EF, FD, DE respectively are concurrent. (Source)

See also

Want to learn how to tackle those tough AMC/AIME/Olympiad algebra problems? Check out Art of Problem Solving's Intermediate Algebra by Richard Rusczyk and Mathew Crawford. Over 1600 problems!
© Copyright 2008 AoPS Incorporated. All Rights Reserved. • FoundationPrivacyContact Us