The Sum of the Exradii Minus the Inradius
The Sum of the Exradii Minus the Inradius
Let ABC be a triangle with circumradius and inradius . Let , , and be the exradii of the excircles opposite A, B, and C, respectively. Then .
R
r
r
A
r
B
r
C
4R=++-r
r
A
r
B
r
C