Chapter 3 Flashcards
Parallel lines
two lines that lie in the same plane and do not intersect
denoted by a ll b, triangles ► are used to indicate that the lines are parallel
Perpendicular lines
two lines that intersect to form a right angle. denoted by
a ┴ b
skew lines
two lines that do not lie in the same plane, skew lines never intersect
Parallel planes
two planes that do not intersect
line perpendicular to a plane
a line that intersects a plane in a point and that is perpendicular to every line in the plane that intersects it.
Theroms 3.1 and 3.2
Perpendicular lines
Theorem 3.1: All right angles are congruent
Theorem 3.2: If two lines are perpendicular , then they intersect to form four right angles
Theorems 3.3 and 3.4
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Theorem 3.3: If two lines intersect to form adjacent congruent angles, then the lines are perpendicular
Theorem 3.4: If two sides of adjacent acute angles are perpendicular, then the angles are complementary
Transversal
a line that intersects two or more coplanar lines at different points
corresponding angles
two angles that occupy corresponding positions
alternate interior angles
two angles that lie between the two lines on the opposite sides of the transversal
alternate exterior angles
two angles that lie outside the two lines on the opposite side of the transversal
same-side interior angles
two angles that lie between the two lines on the same side of the transversal
Postulate 8 “Corresponding angle postulate”
If two parallel lines are cut by a transversal, then correspond angles are congruent
Theorem 3.5 “Alternate interior angles theorem”
If two parallel lines are cut by a transversal, then alternate interior angles are congruent
Theorem 3.6 “ Alternate Exterior angles theorem”
If two parallel lines ate cut by a transversal the alternate exterior angles are congruent
