AP EAMCET2013MathematicsProperties of Triangles
In any A B C, r₁ r₂+r₂ r₃+r₃ r₁ is equal to
Options
- A^2 r^2
- Br
- C2 r
- D^2
Correct answer
A. ^2 r^2
Step-by-step solution
aligned & In A B C, & = s-a s-b + s-b r₁ r₂+r₂ r₃+r₃ r₁ s-c + s-c s-a & = ^2 (s-a)(s-b)(s-c) [s-c+s-a+s-b] aligned aligned & = ^2 3 s-(a+b+c) (s-a)(s-b)(s-c) ( 2 s=a+b+c) & = ^2(3 s-2 s) (s-a)(s-b)(s-c) = ^2 s ( ^2 s ) & [ ^2 s =(s-a)(s-b)(s-c) ] & = s^2 ^2 ^2 = ^2 ( s )^2 = ^2 r^2 [ r= s ] aligned