China -->hk Guest
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Posted: Sun May 27, 2007 10:35 am Post subject: hi,friends(4) |
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hi,friends:
help please.
a quadrilateral ABCD which inscribed in a circle,side AB and side DC meet at(intersect) point E, side AD and side BC meet at(intersect) point F. Bisector line of angle E and bisector line of angle F meet at point P.
How can we use VECTOR proving PE perpendicular to PF?
thanks in advance, |
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