Wheel of Theodorus by Mary Fay-Zenk, Cupertino USD, retired
[email protected] CONCEPT: Geometry SKILLS: Applying the Pythagorean theorem Art by Lexi Katsones in an art context, noting pattern and structure MATH CONTENT STANDARDS: 8.G.7 PREPARATION MATH PRACTICE STANDARDS: 4, 6, 7, 8 Provide students with directions, index cards, GRADES: 6–10 white practice paper, large white paper, pen- MATERIALS: For each student: printed cils, erasers, and straightedges. For upper instructions, one 3 x 5 index card, white grades, provide activity sheets and rulers. practice paper, large white art paper, pencil, eraser, straightedge, colored pencils or PROCEDURE watercolors, and rulers for optional Activity Constructing the Wheel Sheet (p. 37) to be used for upper grades. Constructing the Wheel of Theodorus is an ex- ercise that requires the student to use the valu- able skills of precision and attention to detail BACKGROUND that are found in the Mathematical Practices. One effective exploration of irrational lengths In this approach, we use a method that simpli- also creates a beautiful—even inspiring—spi- fies the process by using the corner of an in- ral design named the Wheel of Theodorus or dex card to “construct” the right angles re- the Spiral of Theodorus. By displaying the spi- quired. A simple 3" x 5" index card works very ral arrangements of a series of right triangles, well for this purpose. Teachers provide the fol- students obtain precise measurements of irra- lowing instructions to students and monitor tional line segments. According to Boaler the progress of their work carefully, especially (2017), “When students think of math visually as they begin to create the appropriate as well as with numbers and symbols, they are triangles.