Four Collinear Points Related to the Altitudes
Four Collinear Points Related to the Altitudes
Let ABC be a triangle. Let A', B', and C' be the feet of the altitudes from A, B, and C. Let P and Q be the projections of A' to AB and AC. Let R and S be the projections of A' to BB' and CC'. Then P, Q, R, and S are collinear.