# A Relation between Altitudes of Four Triangles

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Let ABC be a triangle and DEF be parallel to AC and FGM be parallel to AB. Let AH, DN, FP, and MQ be altitudes in triangles ABC, DBE, FEG, and MGC respectively. Then with the plus sign when F is outside of ABC and minus when F is inside.

Contributed by: Jay Warendorff (March 2011)

After work by: Antonio Gutierrez

Open content licensed under CC BY-NC-SA

## Snapshots

## Details

The statement of the theorem is in Problem 91. Similar Triangles, Altitudes, Parallel.

## Permanent Citation

"A Relation between Altitudes of Four Triangles"

http://demonstrations.wolfram.com/ARelationBetweenAltitudesOfFourTriangles/

Wolfram Demonstrations Project

Published: March 7 2011