Khan Academy on a Stick

Introduction to Euclidean geometry

Roughly 2400 years ago, Euclid of Alexandria wrote Elements which served as the world's geometry textbook until recently. Studied by Abraham Lincoln in order to sharpen his mind and truly appreciate mathematical deduction, it is still the basis of what we consider a first year course in geometry. This tutorial gives a bit of this background and then lays the conceptual foundation of points, lines, circles and planes that we will use as we journey through the world of Euclid.

Algebraically determining segment length

In this tutorial, you'll flex both your algebra and geometry muscles at the same time. You'll do this by applying the right amount of spray tan (which is needed for properly flexing any muscle) and then solve problems about line segments using algebra!