Online Course Discussion Forum

Kurrah's theorem???

 
 
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Kurrah's theorem???
by David Tang - Monday, 28 October 2019, 9:07 PM
 

What is it anyway?

 
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Re: Kurrah's theorem???
by Areteem Professor - Monday, 28 October 2019, 11:17 PM
 
The Kurrah's Theorem is described in Problem 6.10 in the Math Challenge II-B Geometry book.  Here is what it says:

Let $\triangle ABC$ be given. Let $D,E$ be points on $\overline{AC}$ (where $D$ is between $A$ and $E$) such that with $\angle ABC = \angle ADB = \angle BEC$.  Prove that
$$AB^2+BC^2 = AC(AD+CE).$$