In the adjacent figure, 'P' is any arbitrary interior of the triangle ABC, H_a, H_b, H_c are the length of altitudes drawn from vertices A, B and C respectively. If x_a, x_b and x_c represent the distance of 'P' from sides BC, AC and AB respectively, then
xaHa+xbHb+xcHcis always equal to
1
We have,Δ=ΔBPC+ΔAPC+ΔAPB⇒=Δ=12axa+12bxb+12cxcAlso,Δ=12aHa=12bHb=12cHc⇒Δ=Δ(xaHa+xbHb+xcHc)⇒=xaHa+xbHb+xcHc=1