By far the most popular and well-stocked category of used instruments is our selection of guitars, where we've got a huge variety of all the big names. Used Gibson Les Paul, pre-owned Fender Telecaster and secondhand Stratocaster guitars are commonly found within these pages, waiting for their new homes with players and collectors.
22/7 is a pretty decent choice for teaching 11-year-olds about fractions that are close to pi. 355/113 would be better, if you think they can remember numbers that big. And approxRational is fun. Exercise for the interested reader: implement an inverse to approxRational.
Let me first clear some misconceptions about pi. It is not equal to 22/7. That's only a fair estimate which is only accurate until a certain amount of decimal places. The only acceptable âexactâ value of pi is the ratio of circumference of a circle to its diameter. If you're using this pi to derive the âexactâ value of radius given the diameter, the radius (r) becomes r = c/(2*pi). You now substitute pi = C/2r.