Pi Day 2019

Happy "Pi Day"!  Not pie the pastry, but pi the number.  

The number pi is symbolized by the Greek letter π . We use pi to figure the circumference and area of circles and the volume of spheres and cylinders. The circumference of any circle is its diameter times pi.  The area of any circle is its radius squared time pi.  So what does that have to do with today?

Today is the 14th of March.  Otherwise expressed as 3/14 or 3.14.   Just like the number pi!  But, pi doesn't end at 3.14.  The number is thought to be infinite and non-repeating - no one has found the last digit of pi (currently at over one trillion digits and counting) and there is no sequence of numbers that repeats itself within pi!  Written to 100 decimal points pi is...

3.14159265358979323846264338327950288419716939937510582097494459230
78164062862089986280348253421170679...

In celebration of Pi Day, I bought two pies (the pastry) to share at work.  One blueberry pie

and one apple pie.

We are eating pie for mathematics!  This is not just because pi(e) is delicious!

Look at all that math!

Now for a little Pie (pi) related math.  The diameter (the distance across a circle from one side to the opposite side, passing through the center of the circle) of each of these pies is 8.5 inches.  To calculate the circumference (the distance around the perimeter of a circle) we just need to multiply 8.5 inches by pi (3.14).

                  Circumference  = π x diameter

                  Circumference = 3.14 x 8.5 inches

                  Circumference =  26.69 inches

I eat this pie in the name of mathematics!

To calculate the area of the pie we need to know the radius.  Radius is the distance from the center of a circle to the edge of the circle.  This number is one half of the diameter - so if the diameter of these pies is 8.5 inches, the radius would be 8.5 inches divided by 2, which equals 4.25 inches.  The formula for calculating the area of a circle is Area = pi times the radius squared (the radius times the radius). Expressed as a mathematical formula this is A= πr².

                 Area = πr²
           
                 Area = π x (radius x radius)

                 Area = 3.14 x (4.25 inches x 4.25 inches)

                 Area = 3.14 x (18.0625 inches²)

                 Area = 56.71625 inches²

That's 56.71625 square inches of delicious per pie!

If I eat 1/6th of the blueberry pie I am eating 9.4527 square inches of pie (56.71625 x 1/6 = 9.4527 inches²)!  

Math can be delicious!

Remember!  This is for the cause of furthering mathematical knowledge!