For triangle ABC with cevians AD, BE, CF (D ∈ BC, E ∈ CA, F ∈ AB), the three cevians are concurrent iff (BD/DC)(CE/EA)(AF/FB) = +1 (signed ratios). Immediate special cases: medians concur at the centroid; altitudes concur at the…
For triangle ABC with cevians AD, BE, CF (D ∈ BC, E ∈ CA, F ∈ AB), the three cevians are concurrent iff (BD/DC)(CE/EA)(AF/FB) = +1 (signed ratios). Immediate special cases: medians concur at the centroid; altitudes concur at the…