MathDB
TS _|_ BC wanted, altitudes related (Chile NMO 1999 P2)

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November 27, 2021
geometryperpendicular

Problem Statement

In an acute triangle ABCABC, let AK,BL,CM \overline {AK}, \overline {BL}, \overline {CM} be the altitudes of the triangle concurrent at the point H H and let P P the midpoint of AH \overline {AH} . Let's define S=BHMK S = \overline {BH} \cap \overline {MK} and T=LPAB T = \overline {LP} \cap \overline {AB} . Show that TSBC \overline {TS} \perp \overline {BC}