Postulate 2.8 "Ruler Postulate" (HW Postulate 1)
The points on any line or line segment can be paired with real numbers so that given any 2 points, A and B on a line, A corresponds to 0 and B corresponds to a positive real number.
Postulate 2.9 "Segment Addition Postulate" (HW Postulate 2)
If A, B, and C are collinear, and B is between A and C, then AB+BC=AC. or If AB+BC=AC, then B is between A and C.
Postulate 2.10 "Protractor Postulate" (HW Postulate 3)
Given line AB and a number r between 0 and 180, there is exactly one ray with endpoint A, extending on either side of line AB, such that the measure of the angle formed is r.
Postulate 2.11 "Angle Addition Postulate"
If B lies in the interior of <AOC, then m<AOB + m<BOC = m<AOC. If <AOC is a straight angle, and B is any point not on ray AC, then m<AOC + m<BOC = 180.
HW Postulate 5
A line contains at least 2 points; a plane contains at least 3 points not all in one line; space contains at least 4 points not all in one plane.
HW Postulate 7
Through any 3 points, there is at least one plane, and though any 3 noncollinear points there is exactly one plane.
HW Theorem 2-2 "Angle Bisector Theorem"
If ray BX is the bisector of <ABC, then m<ABX=1/2M<ABC and m<XBC=1/2m<ABC.
HW Theorem 2-6
If the exterior sides of 2 adjacent acute angles are perpendicular, then the angles are complementary.
Theorem 2.6 (HW Theorem 2-7)
Angles supplementary to the same angle or to congruent angles are congruent.
Abbr. <'s suppl. to same < or congruent <'s are congruent