If P denotes the perimeter and S denotes the sum of the distances of a point within a triangle from its angular points, then
BO is extended to D
In $$\triangle$$ABD
AB + AD > BD
=> AB + AD > OB + OD ------------Eqn(1)
In $$\triangle$$ODC
OD + DC > OC -------------Eqn(2)
Adding eqn (1) & (2)
AB + AD + OD + DC > OB + OD + OC
=> AB + AC > OB + OC ----------Eqn(3)
Similarly,
BC + BA > OA + OC -----------Eqn(4)
and, CA + CB > OA + OB ----------Eqn(5)
Adding eqns (3),(4) & (5), we get :
2 (AB + BC + CA) > 2 (OA + OB + OC)
=> AB + BC + CA > OA + OB + OC
$$\therefore$$ P > S
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