Pi is the ratio of a circle's circumference to its diameter. It is written on a basketball that the author uses for a school project. The basketball has a circumference of approximately 29 inches and a diameter of 9 inches. Using the formulas, the surface area is calculated to be 254 inches squared, the volume is 381 inches cubed, and the circumference is calculated to be 28.3 inches, close to the measured 29 inches. Pi is important for determining properties of spheres, circles, and other geometric shapes.

1. Pi
By Jack Mulderig

2. Pi (π)
• Pi is the ratio of a circles circumference to its
diameter.
• Therefore, Circumference/Diameter = Pi
• The circumference is proportional to the
diameter and therefore Pi remains constant.
• A sphere is similar to a circle, except it is a
three dimensional shape, and therefore Pi is
applied to spheres.

3. The Basketball
• This is a simple glow in the dark basketball
that I bought for myself a few years ago. I have
always loved it and taken care of it. I always
liked it because its glow in the dark and
bounces pretty darn high (for a basketball).
Now its being used as a school project.
Sacrifices must be made.

4. The Basketball (continued)
Pi is written on the ball, to the extent of :
3.1415926535897932384626433832795028841971693993751058209
7494459230781640628620899862803482534211706798214808651
3282306647093844609550582231725359408128481117450284102
7019385211055596446229489549303819644288109756659334461
2847564823378678316527120190914564856692346034861045432
6648213393607260249141273724587006606315588174881520920
9628292540917153643678925903600113305305488204665213841
4695194151160943305727036575959195309218611738193261179
3105118548074462379962749567351885752724891227938183011
9491298336733624406566430860213949463952247371907021798
60943702770539217176293176752384674818467669405132000568127
145263560827785771342757789609173637178721468440901
224953430146

5. Measurements
• The basketball is approximately 29 inches in
circumference and approximately 9 inches tall

6. Formulas for Spheres
• Surface Area = 4πr2
• Volume = (4/3) πr3
• Circumference = 2πr

7. My sphere (the basketball)
• Since the diameter is 9 inches, the radius must
be 4.5 inches. Therefore, by the given formula,
the Surface area is 81π inches squared, or 254
inches squared. (4×π×4.52)
• The volume is (243/2)π inches cubed, or 381
inches cubed. ((4/3)×π×4.53)
• And finally, the circumference is 9π inches, or
28.3 (which is very close to my measurement
of approximately 29 inches). (2×π×4.5)

8. Conclusion
• Pi is very important for determining the areas
of spheres, circles, angles, sectors, arcs, and
many other applications.