Finding regular polygons, such as equilateral triangles, squares, hexagons, and even octagons, in art or architecture is not unusual, but seeing a nonagon, or nine-sided regular polygon, such as the Mongolian drum (see photograph 1) is less common. Perhaps 9 is a special number in Mongolia: Shamans have 99 tengri, or spirits, (55 benevolent ones and 44 “dark” ones) on their drums, although the drums are more often circular.
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Ahmad M. Alhammouri, Gregory D. Foley, and Kevin Dael
After months of solving real-world problems, high school students enact the full modeling cycle supported by peers, teachers, and technology.
