a median connects a vertex with a midpoint directly across from it, so line JG is your midpoint (you can see the lines on segment KL, showing that both KG and GL are congruent). an altitude drops down a perpendicular line, so line KF is your altitude (you can see the ninety degree box in the corner). an angle bisector bisects, or divides in half, an angle, so JG is also an angle bisector (you can see the lines next to angle J showing that both KJG and GJL are congruent). JG happened to be both a median and an angle bisector, because of the fact that it both bisected angle J (the requirements for an angle bisector) and connected angle J with the midpoint of KL (the requirement for a median). hope this helped