1. SPECIAL SEGMENTS

2. PERPENDICULAR BISECTOR
Segment that is perpendicular to the side and cuts the side into two equal parts. Any point on the perpendicular bisector is equidistant from the endpoints of the segment. Every triangle has 3 perpendicular bisectors. C A B P
If CP is the Perpendicular Bisector of AB, then CA = CB
If CA = CB, then C &P lie on the Perpendicular Bisector of AB

4. MIDSEGMENT
Segment whose endpoints are midpoints of two sides of a triangle. This segment will be parallel to the three such segments. B D E A C
DE = ½ AC

6. MEDIAN BP = 2/3 BF AP = 2/3 AE CP = 2/3 CD
Segment whose endpoints are a vertex of the triangle and the midpoint of the opposite side. Every triangle has 3 medians. B D E P A C F
BP = 2/3 BF
AP = 2/3 AE
CP = 2/3 CD

8. ALTITUDE
Segment whose endpoints are a vertex of the triangle and a point on the line containing the opposite side so that the line formed is perpendicular to the opposite side. Every triangle has three altitudes.
altitude

10. Angle 1 = Angle 2 ANGLE BISECTOR
Segment that bisects an angle of a triangle and has one endpoint at a vertex of the triangle and the other endpoint at another point on the triangle. Any point on the bisector of an angle is equidistant from the sides of the angle. Every triangle has 3 angle bisectors. 1 2
Angle 1 = Angle 2