Geometry Chapter 3.1-3.4 Vocab

Parallel lines

Coplanner lines that never intersect

Skew lines

Non-co-planner lines that never intersect

Perpendicular lines

Two lines that intersect at a 90° angle

Parallel planes

Planes that never intersect

Transversal

A line that intersects two different lines at two different points

Corresponding angles

When two angles are cut by a transversal, angles lie on the same side of the transversal and on the same side of the two line lines

Alternate interior angles

Angles that lie on opposite sides of the transversal, between the two lines and are not a linear pair

Alternate exterior angles

Angles that lie on opposite sides of the transversal, outside of the two lines in are not a linear pair

Same-side interior angles

Angles that lie on the same side of the transversal and between the two lines

Perpendicular bisector

A line, Ray, or segment that is perpendicular to a segment at its midpoint

Distance from a point to a line

The length of the segment from the point perpendicular to the line

Theorem 3-4-1

If two intersecting lines form a linear pair of congruent angles, then the lines are perpendicular

Perpendicular transversal theorem

If a transversal is perpendicular to one of two parallel lines, then it is perpendicular to the other

Corresponding Angles Postulate

If two parallel lines are cut by a transversal, then corresponding angles are congruent.

Alternate Interior Angles Theorem

If two parallel lines are cut by a transversal, then alternate interior angles are congruent.

Alternate Exterior Angles Theorem

If two parallel lines are cut by a transversal, then alternate exterior angles are congruent

Same-Side Interior Angles Theorem

If two parallel lines are cut by a transversal, then same-side interior angles are supplementary

Corresponding Angles Converse

If two lines are cut by a transversal such that corresponding angles are congruent, then the lines are parallel

Alternate Interior Angles Converse

If two lines are cut by a transversal such that alternate interior angles are congruent, then the lines are parallel

Alternate Exterior Angles Converse

If two lines are cut by a transversal such that alternate exterior angles are congruent, then the lines are parallel

Same-Side Interior Angles Converse

If two lines are cut by a transversal such that same-side interior angles are supplementary, then the lines are parallel

Perpendicular Transversal Theorem

In a plane, if a transversal is perpendicular to one of two parallel lines, then it is perpendicular to the other line.

Theorem 3-4-3

If two coplanar lines are perpendicular to the same line, then the two lines are parallel to each other.