# Circles

### Best of the Web

### Websites

**What Pi Looks Like**

A visualization of the many, many known digits of the number π. There's just…so many of them…

### Videos

**Sesame Street: Geometry of Circles**

A Sesame Street video featuring the music of Philip Glass. Some interesting properties of circles show up in the animation. See if you can follow along and describe what's being constructed.

**Where Pi Comes From**

This is a short animation visualizing where π comes from. No, not the bakery.

**Equation of a Circle**

Watch this guy derive the equation for a circle from the distance formula.

**Constructing a Tangent to a Circle**

Put on your hard hat; there's some construction going on here. Today's project: a line tangent to a given circle.

### Games and Tools

**Lost in the Northern Frontier**

In this game, you'll use what is essentially a 2D version of GPS to find a lost astronaut. Circles can save your life, you see.

**Sporcle: Circular Definitions**

Match the circle-related term to its definition as fast as you can.

**Circle Terminology and Practice**

These terminology questions are designed to trip you up. Let logic be your walking stick.

**Geometry: Working with Circles**

You'll know the answers to some of these circle-related questions right away. Others may actually make you think for a few minutes.

**Circle Geometry Review**

A Jeopardy style review game that will make sure you know all the answers…er, questions…when it comes to circles.