MathDB

12

Part of 2010 QEDMO 7th

Problems(1)

AL _|_ BC wanted, altitudes, projections

Source: 7th QEDMO problem 12 (14. - 17. 1. 2010) https://artofproblemsolving.com/community/c1512515_qedmo_200507

5/9/2021
Let YY and ZZ be the feet of the altitudes of a triangle ABCABC drawn from angles BB and CC, respectively. Let UU and VV be the feet of the perpendiculars from YY and ZZ on the straight line BCBC. The straight lines YVYV and ZUZU intersect at a point LL. Prove that AL⊥BCAL \perp BC.
perpendiculargeometry