Best Bay Area deals for Pi Day: here's where you can find all kinds of pie for $3.14

Pie for Pi Day!

It’s Pi Day, an annual celebration of the mathematical constant, which is the ratio of a circle's circumference to its diameter.

The trillion-digit ratio is rounded to 3.14.

Celebrations and promotions have surged in the United States since Congress passed a resolution supporting March 14 as Pi Day. It’s a big deal in education circles and even ancient Egyptians realized it was something special.

By the way, Albert Einstein was born on March 14.

Many restaurants and museums in the Bay Area are offering deals on Pi Day.

Here’s a list:

Exploratorium in San Francisco: Free admission.

Paxti’s Pizza with locations in San Francisco, Lafayette. Get any 14-inch specialty thin crust pizza and get one 10-inch for $3.14.

SOMA: Pi Day Puzzle Party, a math and logic puzzle compettion

Cheeseboard Pizza in Berkeley: Little square pies for $3.14

Pieology Pizza: Buy one artisan thin crust pizza, get another for $3.14.

Firenza Pizza, with locations in San Jose and Los Gatos, is offering its 10-inch cheese pizza for $3.14 on Pi Day.

 Marie Callender’s: Purchase one full-price adult entree and get a free slice of pie (excludes cheesecake and fresh-fruit seasonal pie). Print out the coupon online to take advantage of the deal. Not valid on lunch or happy hour specials. If you miss getting here on Thursday, it’s also Free Pie Monday month, with the same buy-an-entree deal

Whole Foods throughout Bay Area: Large pies will be selling for $3.14 less.

7-Eleven: With the 7Rewards app, get one slice of pizza for 50 cents. Or buy a whole pie in-store and get 314 7Rewards bonus points. With 7NOW, the convenience store chain's delivery service, get up to two whole pizzas for $3.14 each.