If `r_(1), r_(2), r_(3)` in triangle be in H.P., then the sides are :

Explanation

`r_(1) = Delta/(s-a), r_(2) = Delta/(s-b), r_(3) = Delta/(s-c)`
`r_(1), r_(2), r_(3)` are in H.P.
`Delta/(s-a), Delta/(s-b), Delta/(s-c)` are in H.P.
`s-a, s-b, s-c` are in A.P.
`-a,-b,-c` are in A.P.
a,b,c are in A.P.