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Geometry 3 Theorems
Chapter 3 Theorems
Term | Definition |
---|---|
If two parallel lines are cut by a third plane | Then the lines of intersection are parallel |
If two parallel lines are cut by a transversal and alternate interior angles are formed | Then they are congruent |
If two parallel lines are cut by a transversal and same side interior angles are formed | Then they are supplementary |
If a transversal is perpendicular to one of two parallel lines | Then it is perpendicular to the other one also |
If two lines are cut by a transversal and alternate interior angles are congruent or if same side interior angles are supplementary | Then the lines are parallel |
If two lines are perpendicular to the same line in a plane | Then the perpendicular lines are parallel |
Through a point outside a line | There is exactly one line parallel to and perpendicular to the given line |
If two lines are parallel to a third line | Then the lines are parallel to each other |
The sum of the angles of a triangle | 180 |
The measure of an exterior angle of a triangle | Equals the sum of the measures of the two remote interior angles |
The sum of the measures of the angles of a convex polygon | (n-2)180 |
The sum of the measures of the exterior angles of any convex polygon | 360 |