The perpendicular bisector of a side of a triangle is a line <u>perpendicular </u>to the side and passing through its midpoint.
The angle bisector of an angle of a triangle is a straight line that <u>divides the angle</u> into t<u>wo congruent angles</u>.
A median of a triangle is a line segment drawn <u>from a vertex</u> to the <u>midpoint</u> of the opposite side of the vertex.
An altitude of a triangle is the <u>perpendicular</u> segment <u>from a vertex</u> of a triangle <u>to the opposite side</u> (or the line containing the opposite side).
(a) Altitude
m∠KML = 90° but JM ≠ ML (so not perpendicular bisector)
(b) perpendicular bisector
AD = DB and m∠BDE = 90°
(c) median
QS = QR ⇒ S is the midpoint QR, BUT it is not perpendicular to QR, so median