Explains the basic concept of parallel lines in Geometry with step-by-step instructions and methods for solving specific problems on your own relating to this topic.

Explains the basic concept of perpendicular lines with step-by-step instructions and methods for solving specific problems on your own relating to this topic.

Find missing angles given two parallel lines and a transversal. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or receive hints.

This site from Advogato is all about angles. It contains information starting with what an angle is and what it looks like, all the way up to bisecting angles and theorems about angles. This is very good information for students just...

Third graders are preparing to build bat houses. They have calculated surface area, identified nail placement, and will now collect data on angle types in this real-world activity.

Consider two parallel lines that are intersected by a transversal, and when it crosses the two others, many different angle pairs are formed. See the special properties of the angle pairs in this interactive.

Explains the basic concept of lines and angles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.

Provides an introduction to geometry with definitions of points, lines, planes and angles through the use of examples and a brief video lesson. [1:28]

[Free Registration/Login may be required to access all resource tools.] Use alternate exterior angles to determine congruency and the presence of parallel lines.

Study inscribed angles in semicircles and quarter-circles. What conjectures can you make about the measure of an inscribed angle in semi- or quarter-circles?

[Free Registration/Login Required] Students explore the concept of perpendicular lines by navigating through the interactive learning module and then answering questions that go along with the module. Students can also learn more about...

[Free Registration/Login may be required to access all resource tools.] This study guide looks at proportionality theorems for triangles and parallel lines intersected by transversals.

Given algebraic expressions that represent a pair of two vertical angles, form and solve an equation. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

[Free Registration/Login may be required to access all resource tools.] Students watch a video and attempt practice problems about parallel lines cut by a transversal.

[Free Registration/Login may be required to access all resource tools.] Identify adjacent and vertical angles formed by intersecting lines and then find missing angle measures.

[Free Registration/Login may be required to access all resource tools.] Identify adjacent and vertical angles formed by intersecting lines and then find missing angle measures.

Students can review basic geometric terms using these self-check, multiple choice questions. Three levels of questions are provided.

In this activity, students use the Cabri software to mark points, draw lines, construct parallel and perpendicular lines, angles, bisectors, and triangles. They learn how to use the tool to measure angles.

Use the Desmos transformation tools (link at top of page) to complete this scavenger hunt. There are three levels to choose from and solutions are included.

This site provides definitions of different types of polygons and figures.

This site defines eleven theorems relating to parallel lines and similar and congruent triangles. Links to the theorems and relevant term descriptions are provided.

This site defines parallel lines, parallel lines cut by a transverse, and congruent triangles. It also contains links for related terms.

Explores how to measure the length of a line segment through examples and a video lesson. [0:40]

[Free Registration/Login Required] Explore the relationships between parallel lines and the rules of angle measurements.