The Sum of the Reciprocals of the Exradii
The Sum of the Reciprocals of the Exradii
Let ABC be a triangle with inradius . Let , , and be the exradii of the excircles opposite A, B, and C, respectively. Then =++.
r
r
A
r
B
r
C
1
r
1
r
A
1
r
B
1
r
C