Question

Prove that: $a+b+c=\frac{abc}{2Rr}$

Answer 1

$\frac{abc}{2Rr}=\frac{abc}{2}\times \frac{1}{R}\times \frac{1}{r}=\frac{abc}{2}\times \frac{4\Delta }{abc}\times \frac{s}{\Delta }=2s=a+b+c=L.H.S$