Chapter 4: Parallel Lines Flashcards
Lines, segments, rays, or points which lie in the same plane are said to be
coplanar
Parallel lines are
lines that lie in the same plane (coplanar) and that never intersect
A transversal is
a line that intersects two or more lines in different points
Postulate 6: If two parallel lines are cut by a transversal, then
their alternate interior angles are congruent (equal)
Theorem 9: If two parallel lines are cut (crossed) by a transversal, then
their corresponding angles are congruent (equal)
Theorem 10: If the two angles in a linear pair have equal measures (are congruent), then
each is a right angle
Theorem 11: If two parallel lines are cut (crossed) by a transversal, then
their alternate exterior angles are congruent (equal)
Theorem 12: If two parallel lines are cut (crossed) by a transversal, then
interior angles on the same side of the transversal are supplementary
Postulate 7: If two lines form congruent alternate interior angles with a transversal, then
the lines are parallel
Theorem 13: If two lines form congruent corresponding angles with a transversal, then
the lines are parallel
Theorem 14: If two lines form congruent alternate exterior angles with a transversal, then
the lines are parallel
Theorem 15: If two lines form supplementary interior angles on the same side of a transversal, then
the lines are parallel