Math in Books and Film

In Arthur Conan Doyle's The Musgrave Ritual, Sherlock Holmes uses geometry to solve a 250 year mystery:

"Well, at least I knew that if Brunton could do it, I could also. Besides, there was no real difficulty. I went with Musgrave to his study and whittled myself this peg, to which I tied this long string with a knot at each yard. Then I took two lengths of a fishing-rod, which came to just six feet, and I went back with my client to where the elm had been. The sun was just grazing the top of the oak. I fastened the rod on end, marked out the direction of the shadow, and measured it. It was nine feet in length.

"Of course the calculation now was a simple one. If a rod of
six feet threw a shadow of nine, a tree of sixty-four feet would
throw one of ninety-six, and the line of the one would of course be the line of the other."

Of course, this is an old idea, and how Thales measured the height of Egyptian pyramids some 500 years B.C. For more Math at the movies, check out Mathematics in Movies (includes clips) and Math In the Movies or Mathematical Fiction for books.



Sherlock Holmes image from Wikimedia