Pi is a number - expressed to the ten-thousandths place it read as 3.1415. 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.
Just for fun I bought two pies to celebrate Pi Day.
|Celebrating Pi Day with blueberry pie (left) and caramel apple pie (right)|
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
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!
|Math makes pie more delicious!|