Texas Education Agency
Texas Gateway: Parallel and Intersecting Lines
This activity provides an opportunity for students to build an understanding of parallel and intersecting lines.
CK-12 Foundation
Ck 12: Geometry: Lines and Angles Study Guide
This study guide on lines and angles covers key terminology; line notation; parallel, perpendicular, and skew lines; and postulates and theorems about lines. It is available for download with free registration.
Illustrative Mathematics
Illustrative Mathematics: 8.g Congruence of Alternate Interior Angles
Eighth graders are presented with a labeled drawing of two parallel lines intersected by a transversal line. They are asked to discuss congruency of angles when the picture is rotated about a point on the transversal. Aligns with 8.G.A.5.
Math Planet
Math Planet: Pre Algebra: Geometry Fundamental Statements
Provides examples and a video lesson that introduce fundamental statements of geometry.