This study guide on lines in a coordinate plane covers key terms, what different line slopes look like, postulates about parallel and perpendicular lines, the slope-intercept equation, how to graph parallel and perpendicular lines, and...

A comprehensive guide for learning all about Coordinate geometry with definitions, the coordinate plane, formulas, equation of a line, related topics, solved examples, and practice questions.

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.

Alex and his friends are studying for a geometry test and one of the main topics covered is parallel lines. They each write down what they think it means for two distinct lines in a plane to be parallel. Students are asked to analyze...

[Free Registration/Login may be required to access all resource tools.] This concept teaches students about tangent lines and how to apply theorems related to tangents of circles.

Explains angles and parallel lines through examples and a video lesson.

Reflect any point, line segment, triangle, or any other figure over one or two lines using this dynamic applet. Points and lines are entered by point-and-click rather than by typing equations or ordered pairs. A very neat exercise to...

Explore the world of transversals in this mini-lesson. Learn about transversals, transversal lines, and angles. There are transversal examples and a few interesting practice questions at the end of the page to strengthen your concepts of...

Here is a partial list of theorems, postulates, and properties.

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...

This task uses GeoGebra software, which can be freely downloaded, to explore what happens to the line segments and angles of a triangle when it is reflected, rotated, and translated. Includes printable task sheet for students and a...

Scroll down to find a definition of horizontal with hyperlinks to other definitions on the site.

Learners explore the definitions and properties of the perpendicular bisector. The interactive activity includes an applet to explore the properties of the perpendicular bisector.

For this task, students are shown a unit circle in a plane and an angle measured from the x-axis. They must determine the coordinates of the line segment for the angle and answer a question about the sum of the coordinates. The purpose...

This site offers numerous activities for middle school and high school learners to explore using Geometer's Sketch Pad.