Geometry

Points, lines, and planes

This topic introduces the basic conceptual tools that underpin our journey through Euclidean geometry. These include the ideas of points, lines, line segments, rays, and planes.

Angles and intersecting lines

This topic continues our journey through the world of Euclid by helping us understand angles and how they can relate to each other.

Congruent triangles

If you can take one figure and flip, shift and rotate (not resize) it to be identical to another figure, then the two figures are congruent. This topic explores this foundational idea in geometry.

Perimeter, area and volume

A broad set of tutorials covering perimeter area and volume with and without algebra.

Right triangles

Triangles are not always right (although they are never wrong), but when they are it opens up an exciting world of possibilities. Not only are right triangles cool in their own right (pun intended), they are the basis of very important ideas in analytic geometry (the distance between two points in space) and trigonometry.

Special properties and parts of triangles

You probably like triangles. You think they are useful. They show up a lot. What you'll see in this topic is that they are far more magical and mystical than you ever imagined!

Quadrilaterals

Not all things with four sides have to be squares or rectangles! We will now broaden our understanding of quadrilaterals!

Logical reasoning

If you experience this tutorial, then you will think clearer. My dog thinks clearly. Did he definitely experience this tutorial?

Transformations

Let's think more visually about things like shifts, rotations, scaling and symmetry.

Worked Examples

Sal does the 80 problems from the released questions from the California Standards Test for Geometry. Basic understanding of Algebra I necessary.