WOLFRAM|DEMONSTRATIONS PROJECT

Triangle Altitudes and Inradius

​
1
inradius[ABC]
≈
0.226
1
AA'
+
1
BB'
+
1
CC'
≈
0.226
If a triangle has inradius
r
and altitudes
α
,
β
, and
γ
, then
1
r
=
1
α
+
1
β
+
1
γ
.