| A | B |
|---|
| Parallel Lines | Two lines that are coplanar and do not intersect |
| Skew lines | Lines that do not intersect and are not coplanar |
| Parallel planes | Two planes that do not intersect |
| Transversal | A line that intersects two or more coplanar lines at different points |
| Corresponding angles | When two lines are cut by a transversal, two angles that occupy corresponding positions |
| Alternate exterior angles | When two lines are cut by a transversal, two angles that lie outside the two lines on opposite sides of the transversal |
| Alternate interior angles | When two lines are cut by a transversal, two angles that lie between the two lines on opposite sides of the transversal |
| Consecutive interior angles | When two lines are cut by a transversal, two angles that that lie between the two lines on the same side of the transversal |
| Parallel Postulate | If there is a line and a point not on the line, then there is exactly one line through the point parallel to the given line |
| Perpendicular Postulate | If there is a line and a point not on the line, then there is exactly one line through the point perpendicular to the given line |
| If two lines intersect to form a linear pair of congruent angles, | then the lines are perpendicular. |
| If two sides of two adjacent acute angles are perpendicular, | then the angles are complementary. |
| If two lines are perpendicular, | then they intersect to form four right angles |
| Corresponding Angles Postulate | If two parallel lines are cut by a transversal, then the pairs of corresponding angles are congruent. |
| If two parallel lines are cut by a transversal, then the pairs of alternate interior angles are | congruent |
| If two parallel lines are cut by a transversal, then the pairs of consecutive interior angles are supplementary. | supplementary |
| If two parallel lines are cut by a transversal, then the pairs of alternate exterior angles are | congruent |
| If a transversal is perpendicular to one of two parallel lines, then it is perpendicular to the other. | perpendicular to the other |
| Corresponding Angles Converse | If two lines are cut by a transversal so that corresponding angles are congruent, then the lines are parallel |
| Alternate Interior Angles Converse | If two lines are cut by a transversal so that alternate interior angles are congruent, then the lines are parallel. |
| Consecutive Interior Angles Converse | If two lines are cut by a transversal so that consecutive interior angles are supplementary, then the lines are parallel |
| Alternate Exterior Angles Converse | If two lines are cut by a transversal so that alternate exterior angles are congruent, then the lines are parallel |
| If two lines are parallel to the same line, | then they are parallel to each other. |
| In a plane, if two lines are perpendicular to the same line, | then they are parallel to each other. |
| Parallel Postulate | Given a line and a point not on the line, there is one and only one line that contains the given point and is parallel to the given line. |
| Triangle Sum Theorem | The sum of the measures of the angles of a triangle is 180 degrees. |
| Exterior Angle Theorem | The measure of an exterior angle of a triangle is equal to the sum of the measures of the remote interior angles. |
| Sum of the Interior Angles of a Polygon | The sum, s, of the measures of the interior angles of a polygon with n sides is given by s=(n-2)180 |
| Measure of an Interior Angle of a Regular Polygon | The measure, m, of an interior angle of a regular polygon with n sides is m=[(n-2)180]/2 |
| Sum of the Exterior Angles of a Polygon | is equal to 360 degrees |
| Paralell Lines Theorem | In a coordinate plane, two nonvertical lines are parallel if and only if they have the same slope. |
| Perpendicular Lines Theorem | In a coordinate plane, two nonvertical lines are perpendicular if and only if the product of their slopes is -1. |
