Multiplying and Dividing Irrationally
This chapter describes how to multiply and divide, albeit approximately, by some of the world’s most famous irrational numbers, such as π, Euler’s number e, 2, 3, both of which occur frequently in the study of triangles, and the Golden Ratio, also sometimes called the Divine proportion. The approximations for π stem from the Ancient World, including the Hebrew Bible, Greek, and Babylonian approximations. An example for 2 is provided by the medieval Jewish polymath, Maimonides. By use of various approximations, the sine of some angles can be easily computed, which can impress those with a grasp of elementary trigonometry. Some examples of “almost” formulas are presented.