Khan Academy: Geometry: Angles Formed by Parallel Lines and Transversals

Use the parallel lines to find your way. After first reviewing geometric constructions and the relationships between angles formed by parallel lines and a transversal, young mathematicians write proofs for theorems relating to parallel...

Segment transversals proportionally. Given a diagram with three parallel lines and two transversals, the narrator of a short video points out the parallel lines cut the transversals proportionally. The portion of a long playlist on...

This resource explores parallel lines and requires students to practice calculations and analyze angles. By asking viewers to decide whether two lines are parallel based on the information given, this second part of the parallel lines...

Providing an exploration of parallel lines, this resource requires students to not only practice calculations, but also to analyze angles. By asking viewers to decide whether two lines are parallel based upon the information given, this...

Explains the relationship between the measures of angles formed when parallel lines are cut by a transversal based on relationships of corresponding, vertical, and supplementary angles. [7:53]

Proof that the sum of the angles in a triangle is 180 using the relationship of angles formed when parallel lines are cut by a transversal. This video also appears in the Geometry: Triangles strand. [6:31]

Students can use Cabri Jr. to construct parallel lines and transversals. They will make conjectures about the angles that are formed.

Young scholars explore the concept of angles formed by parallel lines.They graph two parallel lines cut by a transversal, then measure the angles formed by the transversal and record the data in a table. Learners make conjectures about...

Explains how to determine the measures of angles formed by interecting lines when given the measure of one angle. [7:19]

Explains how to identify and use similar triangles in order to determine unknown side lengths in two given diagrams. Each diagram also applies knowledge of angles formed when parallel lines are cut by a transversal. [7:37]