Education Technology

Year 9: Spirally Surds

by Roger Wander


The purpose of this activity is to engage students in the lovely visual representation (Spiral of Theodorus) and see how it provides a natural progression of a series of surds. 


  • Surd
  • Spiral of Theodorus
  • Perpendicular

About the Lesson

In this activity students use traditional pencil and paper techniques to construct the Spiral of Theodorus, after which they use the Geometry application on TI-Nspire to make the spiral dynamic. Students then explore consecutive hypotenuse, a series of surds, helping connect geometry and number.