Question

If ex-radii r₁, r₂, r₃ of a triangle are in HP then its sides a, b, c are in

(A) AP 

(B) GP 

(C) HP 

(D) None of these

Answer 1

Correct option  (A)  AP

1/r₁ - 1/r₂ = 1/r_{2 -} 1/r₃

So a, b, c are in AP.