Plato's Protractor™ - V
In this activity the Mathomat kids are presented with the Ferris wheels from the earlier All about pi activity in the Explorer manual in nested form. They are encouraged to see radians as a way of simplifying circles so that distances can be measured. They do this by measuring distance travelled around the circumference of each wheel for a common angle. This builds on the notion that what is being measured in angle measure is openness, and that radians and degrees are simply different units for measuring the same underlying concept. The curved line used in an angle representation can be seen in this activity as representing a family of subtended arcs that are associated with that particular angle.