2. Equality created by an angle bisector. An angle bisector creates 2 equal halves. Definition of an angle bisector.
5. Equals substituted for equals leaves the condition unchanged. You really don't have anything for this. Each one of these blanks has it's own choices. You want something that talks about substituting an equal for another equal.
6. None of your choices work here either. Angle addition postulate is about the closest one. 2 equal parts added together equal the whole. The whole is twice as big as either one of the two equals. Together the 2 equals add up to the entire angle.
