# Thread: problem in properties of triangles

1. ## problem in properties of triangles

if a,b,c be the radii of three circles which touch oneanother externally and r1 and r2 be the radii of two circles that can be drawn to touch these three then prove that
1/r1 -1/r2 = 2{1/a+1/b+1/c}

This problem is from s l loney. Kindly help me with the solution.

2. Originally Posted by chandrasekhar_mallisetty
if a,b,c be the radii of three circles which touch oneanother externally and r1 and r2 be the radii of two circles that can be drawn to touch these three then prove that
1/r1 -1/r2 = 2{1/a+1/b+1/c}

This problem is from s l loney. Kindly help me with the solution.
You'll have to be a bit more specific on the $\displaystyle r_1$ and $\displaystyle r_2$ parts. I'm not sure how these two circles are supposed to be drawn.