The 4 types of reasons that may be used in a proof are. Given Information 2. If two angles are straight angles then they are congruent. This can be proven the same way as above, just substitute, straight for right angles and replace 90 with 180. MB Definitions are reversible.
Every segment has exactly one midpoint.
If a segment is divided into 3 congruent segments, then it is said to be trisected. Angle Bisector - The bisector of an angle is the ray that divides the angle into two congruent angles. Every angle has exactly one bisector. If an angle is trisected, then two rays divided the angle into 3 congruent angles. The rays are said to be trisectors of the angle.