3-2 geometry
theorem 3-3: alternate exterior angles theorem
if a transversal intersects two parallel lines, then alternate exterior angles are congruent.
theorem 3-1: alternate interior angles theorem
if a transversal intersects two parallel lines, then alternate interior angles are congruent.
theorem 3-2: corresponding angles theorem
if a transversal intersects two parallel lines, then corresponding angles are congruent.
postulate 3-1: same-side interior angles postulate
if a transversal intersects two parallel lines, then same-side interior angles are supplementary.
theorem 3-7: converse of the alternate exterior angles theorem
if two lines and a transversal form alternate exterior angles that are congruent, then the two lines are parallel.
theorem 3-5: converse of alternate interior angles theorem
if two lines and a transversal form alternate interior angles that are congruent, then the two lines are parallel.
theorem 3-4: converse of the corresponding angles theorem
if two lines and a transversal form corresponding angles that are congruent, then the lines are parallel.
theorem 3-6: converse of the same-side interior angles postulate
if two lines and a transversal form same-side interior angles that are supplementary, then the two lines are parallel.
theorem 3-8
if two lines are parallel to the same line, then they are parallel to each other.
theorem 3-10: perpendicular transversal theorem
in a plane, if a line is perpendicular to one of two parallel lines, then it is also perpendicular to the other.
theorem 3-9
in a plane, if two lines are perpendicular to the same line, then they are parallel to each other.