Know precise definitions of angle, circle, perpendicular line, parallel line, and line segment, based on the undefined notions of point, line, distance along a line, and distance around a circular arc.

What is a Point?

A point is a fundamental building block of math. Without points, you couldn't make lines, planes, angles, or polygons. That also means that graphing would be impossible. Needless to say, learning about points is very important! That makes this tutorial a must see!
What is a Line Segment?

A math term can really tell you a lot about the thing it's describing. Take the term line segment. A line segment is just part of a line! In this tutorial, learn about line segments, how to name them, and what the midpoint of a line segment is!
What is an Angle?

Angles are a fundamental building block for creating all sorts of shapes! In this tutorial, learn about how an angle is formed, how to name an angle, and how an angle is measured. Take a look!
What are Parallel Lines?

Lines that are parallel have a very special quality. Without this quality, these lines are not parallel. In this tutorial, take a look at parallel lines and see how they are different from any other kind of lines!
What are Perpendicular Lines?

Perpendicular lines have a special property. The angles formed by perpendicular lines will always be the same. Check out this tutorial to learn about perpendicular lines and see a cool trick involving these special lines!
What is a Circle?

Circles are a fundamental part of math! In this tutorial, you'll be introduced to circles and see the different parts of a circle such as the diameter, radius, and chord. Check out this tutorial to learn about circles!