Did you know that aside from being a source of news, The New York Times is also the place to get your weekly fix of mathematics? Their online Numberplay column features some very clever math puzzles. Last year, in fact, our blog featured a Numberplay puzzle about a flying squirrel-frog from former Key Curriculum editor, Dan Bennett.

Last week’s puzzle caught my attention because it seemed tailor made for Sketchpad. I’ve described the puzzle in the Web Sketchpad model below, but you can learn about its origins from the mysteriously named Dr. W, who first brought the puzzle to the attention of the Numberplay editor.

I recommend trying the puzzle first before viewing my solutions on the second, third, and fourth pages of the Web Sketchpad model. (Use the arrows in the lower-right corner to navigate between pages.) Dr. W recommends building yourself a physical model of the triangles. Indeed the puzzle makes a fine hands-on challenge for children.

You’ll notice that nowhere in my Web Sketchpad model do I prove any results. That’s left for you!