## Desert Diary

Math/Pi Day

March 14th, or as we write it 3/14, is Pi Day! Math classes and museums
from coast to coast are celebrating that special number that begins three point one
four. PI comes from dividing the distance *around* a circle by the greatest
distance *across* the circle: circumference divided by diameter.

There are circles among our *cultural* exhibits such as a basket,
wheel, and drum. Circles are a great shape for drum heads because they have the most
area for a given perimeter and the shape represents oneness with the universe to Native
Americans. There are also *natural* desert phenomena whose cross-sections are
circles, such as eggs, cacti, and snakes.

Now what if you were lost in the desert and tried to leave by walking a
straight line? Despite your best efforts, you'd probably turn a little with each
step and end up walking a big circle back to where you started. So even in the desert,
finding circles can be easy as pi.

Contributor: Lawrence M. Lesser, Mathematical
Sciences, University of Texas at El Paso.

Desert Diary is a joint production of the Centennial Museum and KTEP
National Public Radio at the University of Texas at El Paso.

*The Greek letter pi has been used to symbolize the relationship between the
circumference and the diameter of a circle since 1706.*

## References

Lawrence M. Lesser. 2004. Slices of Pi: Rounding up ideas for
celebrating Pi Day. Texas Mathematics Teacher, 51(2):6-11.

### Web Resources

American Pi, a
mathematics' song.

Math Forum