# The Semiperimeter and Tangents to Excircles

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Let ABC be a triangle. Construct the excircle opposite A and let D and E be the intersections of the extensions of AB and AC with the excircle. Let be the semiperimeter of ABC. Then = AD = AE.

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 140. Triangle, Excircle, Tangent, Semiperimeter.

## Permanent Citation

"The Semiperimeter and Tangents to Excircles"

http://demonstrations.wolfram.com/TheSemiperimeterAndTangentsToExcircles/

Wolfram Demonstrations Project

Published: March 7 2011