Difference between revisions of "1997 USAMO Problems/Problem 2"
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==See Also== | ==See Also== | ||
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[[Category:Olympiad Geometry Problems]] | [[Category:Olympiad Geometry Problems]] |
Revision as of 16:13, 12 April 2012
Problem
is a triangle. Take points
on the perpendicular bisectors of
respectively. Show that the lines through
perpendicular to
respectively are concurrent.
Solution
This problem needs a solution. If you have a solution for it, please help us out by adding it.
Let the perpendicular from A meet FE at A'. Define B' and C' similiarly. By Carnot's Thereom, The three lines are concurrent if
![$FA'^2-EA'^2+EC'^2-DC'^2+DB'^2-FB'^2 = AF^2-AE^2+CE^2-CD^2+BD^2-BF^2 = 0$](http://latex.artofproblemsolving.com/d/6/b/d6b20981adfbb3753b05f37c72c3239f774fc7c2.png)
But this is clearly true, since D lies on the perpendicular bisector of BC, BD = DC.
QED
See Also
1997 USAMO (Problems • Resources) | ||
Preceded by Problem 1 |
Followed by Problem 3 | |
1 • 2 • 3 • 4 • 5 • 6 | ||
All USAMO Problems and Solutions |