In a △ABC, the inradius is r and three exradii are r1,r2 and r3 respectably. In usual notations the value of r.r1.r2.r3 is equal to
2∆
∆2
None of these
r.r1.r2.r3=△s.△s−a.△s−b.△s−c=△4△2=△2