Happy Pi Day!

It's March 14, which means it's Pi Day!

To celebrate, we've compiled a list of our favorite interactive lessons involving pi:

Circumference and pi

Find the distance around a circle (and then eat some pi). And maybe get a head start on memorizing pi's digits?

Circle area

Using circumference to find a circle's area. If you've never worked through this proof before, you'll definitely want to check it out!


Discover another way to measure angles. There's more to angles than just degrees...

Sector area

If you're eating a slice of pie, discover a sure-fire way to find its area!

Sine, cosine, and tangent functions

We've completely reworked our introduction to trigonometry, and those infamous trig functions. Play with interactive right triangles as you learn about these functions, and discover what they can do!

In other news, our probability-based game "Beat the Odds" has been named a winner of WGBH's Education Innovation Challenge! (And they even made a video about us.)

And on a final note, we're hard at work producing lessons on trigonometry and volumes of solids, and many of those formulas also have a pi floating around! Here's a teaser of what's to come: