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.

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.

Learn about corresponding angles with this resource which offers detailed explanations and examples. Subjects covered include parallel and non-parallel cases. Links to related topics.

Explore the triangle inequality theorem with this helpful reference tool. Provides a detailed definition and an interactive activity that enhances further explanation. Includes links to related topics.

A "convention" is "just the way a thing is done!". This reference material lists some common conventions (notational assumptions) for geometry and trigonometry.

For this task, young scholars must prove that angles and triangles are congruent and that a parallel line passes through the midpoints of two sides of the larger triangle. Aligns with G-SRT.B.4.

For this task, students are asked to draw a quadrilateral so that no two sides are congruent, no two angles are congruent, and no two sides are parallel. The task gives students the opportunity to prove that if we join the midpoints of a...