# A Collinearity between the Nine-Point Center, the Foot of an Altitude, and a Midpoint

A Collinearity between the Nine-Point Center, the Foot of an Altitude, and a Midpoint

Let ABC be a triangle with nine-point center N. Let B' be the foot of the altitude from B. Let the circumdiameter through B intersect AC at D. Let the midpoint of BD be M. Then M, N, and B' are collinear.