Geometric Function
About the "Geometric Function" activity is: it starts with a geometric situation and using the dragging action, the task is to identified two variables in relation and describe their behavior. In a second moment, the graph of the function is constructed as a trace of a point, only using a geometric procedure. The activity explores the notion of variability and the independence/dependence relation; the stress on the function expression is the final part of the work.
Some others ideas of geometric situations can be seen in Geometric Function examples