Geometry Section 2.8
theorem 2
If the non common sides of two adjacent angles form a right angle, then the angles are complementary angles
theorem 1
If two angles form a linear pair, then they are supplementary angles
theorem 7
all right angles are congruent
reflexive property of congruent angles
angle ABC is congruent to angle ABC
theorem 4
angles complementary to the same angle or to congruent angles are congruent
theorem 3
angles supplementary to the same angle or to congruent angles are congruent
protractor postulate
given AB and a number r between 0 and 180, there is exactly one ray with endpoint A extending on either side of AB such that the measure of the angle formed is r
angle addition postulate
if R is in the interior of angle PQS, then the measure of angle PQR plus the measure of angle RQS equals the measure of angle PQS. If the measure of angle PQR plus the measure of angle RQS equals the measure of angle PQS, then R is in the interior of angle PQS
transitive property of congruent angles
if angle ABC is congruent to angle DEF and angle DEF is congruent to angle GHI, then angle ABC is congruent to angle GHI
symmetric property of congruent angles
if angle ABC is congruent to angle DEF, then angle DEF is congruent to angle ABC
theorem 9
if two angles are congruent and supplementary, then each angle is a right angle
theorem 5
if two angles are vertical angles, then they are congruent
theorem 10
if two congruent angles from a linear pair, then they are right angles
theorem 8
perpendicular lines form congruent adjacent angles
theorem 6
perpendicular lines intersect to form four right angles