In `DeltaABC, Delta = 6, abc = 60, r=1`. Then the value of `(1)/(a) + (1)/(b) + (1)/(c)` is nearly

Options

A. `0.5`
B. 0.6
C. 0.4
D. 0.8

Answer

D

Explanation

`r=(Delta)/(s) =1 rArr s =6`
`:. (s-a) (s-b)(s-c) = s`
`rArr s^(3) - (a +b +c)s^(2) + (ab + bc + ca)s -abc = s`
`rArr 6^(3) - 12 xx 36 + (ab + bc +ca) - 60 = 6`
`rArr ab + bc + ca = 47`
`:' (1)/(a) + (1)/(b) + (1)/(c) = (47)/(60) = 0.8` (nearly)