This Greek letter represents the ratio of a circle's circumference to its diameter.

Pi Day is celebrated on this date.
What is March 14?
The distance from the center of a circle to it's edge.
What is the radius?
The first digit of pi after the decimal.
What is 1?
Pi is used when working with anything shaped like this.
What is a circle?
Pi is approximately equal to this number.
What is 3.14?
This date format matches the first three digits of pi.
What is 3/14?
The distance across a circle through its center.
What is the diameter?
The first three digits of pi.
What is 3.14?
Wheels, pipes, and conveyor rollers rely on this shape.
What is a cylinder or circle?
Pi is classified as this type of number because it never ends or repeats.
What is an irrational number?
This famous scientist was born on Pi Day
Who is Albert Einstein?
The distance around the outside of a circle.
What is the circumference?
True or false: Pi eventually ends.
What is false?
Engineers use pi when calculating this for circular objects.
What is area of circumference?
Pi has been calculated to more than this many digits worldwide.
What is trillions of digits?
This dessert is traditionally eaten on Pi Day.
What is pie?
If the radius of a circle doubles, the area does this.
What is quadruples?
This is what we call someone who memorizes many digits of pi.
What is a pi memorization champion?
(Accept: pi enthusiast)
This career regularly uses pi when designing machines and structures.
What is engineering?
(Accept: architecture, physics, manufacturing)
Pi is named after this Greek word meaning "perimeter."
What is perimetros?
Pi Day was officially recognized by the U.S House of Representatives in this year.
What is 2009?
If the diameter of a circle is 10 units, this is the radius used in circle formulas.
What is 5 units?
The world record holder memorized more than this many digits of pi.
What is over 70,000 digits?
Pi helps calculate volume for this 3D shape.
What is a sphere or cylinder?