WOLFRAM|DEMONSTRATIONS PROJECT

Another Relation between the Areas of Triangles Associated with an Excircle

​
S
1
≈
7.04
S
2
≈
2.41
S
3
≈
4.62
S
2
+
S
3
≈
7.04
Let ABC be a triangle. Let D and E be the points of contact of the incircle of ABC with AB and AC. Let J be the excenter of the excircle opposite A and let G and F be the intersections of DJ and EJ with BC. Let
S
1
,
S
2
, and
S
3
be the areas of GJF, DBG, and ECF, respectively. Then
S
1
=
S
2
+
S
3
.