Parallel Lines
Coplanar lines that do not intersect.
Skew Lines
Lines that do not intersect and are not coplanar.
Parallel Planes
Planes that do not intersect.
Transversal
A line that intersects two or more lines in a plane at different points,
Interior Angles
Angles that lie between two transversals that intersect the same line.
Exterior Angles
Angles formed by one side of a triangle and the extension of another side.
Consecutive Interior Angles
Interior angles that lie on the side of a transversal.
Alternate Interior Angles
Nonadjacent interior angles that lie on opposite sides of a transversal.
Alternate Exterior Angles
Nonadjacent exterior angles that lie on opposite sides of a transversal.
Corresponding Angles
Angles that lie on the same side of a transversal and on the same sides of lines.
Corresponding Angles Postulate
If two parallel lines are cut by a transversal, then each pair of corresponding angles is congruent.
Alternate Interior Angles Theorem
If two parallel lines are cut by a transversal, then each par of alternate interior angles is congruent.
Consecutive Interior Angles Theorem
If two parallel lines are cut by a transversal, then each pair of consecutive interior angles is supplementary.
Alternate Exterior Angles Theorem
If two parallel lines are cut by a transversal, then each pair of alternate exterior angles is congruent.
Perpendicular TransVersal Theorem
In a plane, if a line is perpendicular to one of two parallel lines, then it is perpendicular to the other.
Slope
The ratio of the change along the y-axis to the change along the x-axis between any two points on the line.
Rate of Change
Describes how a quantity is changing over time.
Slopes of parallel lines postulate
Two nonvertical lines have the same slope if and only if they are parallel. All vertical lines are parallel.
Slopes of perpendicular lines postulate
Two nonvertical lines are perpendicular if and only if the product of their slopes is -1. Vertical and horizontal lines are perpendicular.
Slope Intercept Formula
y = mx + b
Point - Slope Formula
y - y1 = m (x - x1)
Standard Form
ax + by = c
Converse of Corresponding Angles Postulate
If two lines are cut by a transversal so that corresponding angles are congruent, then the lines are parallel.
Parallel Postulate
If given a line and a point not on the line, then there exists exactly one line through the point that is parallel to the given line.
Alternate Exterior Angles Converse
If two lines in a plane are cut by a transversal so that a pair of alternate exterior angles is congruent, then the two lines are parallel.
Consecutive Interior Angles Converse
If two lines in a plane are cut by a transversal so that a pair of consecutive interior angles is supplementary, then the lines are parallel.
Alternate Interior Angles Converse
If two lines in a plane are cut by a transversal so that a pair of alternate interior angles is congruent then the lines are parallel.
Perpendicular Transversal Converse
In a plane, if two lines are perpendicular to the same line, then they are parallel.
Perpendicular Postulate
If a given line and a point not on the line, then there exists exactly one line through the point that is perpendicular to the given line.
Equidistant
The distance between two lines measured along a perpendicular line is always the same.
Two Lines Equidistant from a Third
In a plane, if two lines are each equidistant from a third line, then the two lines are parallel to each other.