Define an Angle
Instructions
Background
Just what is an “angle?”
It turns out that geometers have a very specific definition for an angle.
This GeoGebra activity will help you understand the geometer’s definition of angle.
Step 1. Follow the Recipe
Use the MOVE 
tool to click in order on the recipe steps.
Step 2. Experiment with the Angle
Your angle is defined by the three points A, B, and C.
Use the MOVE tool to drag these points about and observe the results.
Step 3. Make Your Own Angle
Use the MOVE tool to click off all of the recipe steps and clear the work-space.
Use the NEW POINT tool 
and the RAY THROUGH TWO POINTS tool 
to create your own angle by following the instructions in the recipe steps.
tool to click in order on the recipe steps.
Step 2. Experiment with the Angle
Your angle is defined by the three points A, B, and C.
Use the MOVE tool to drag these points about and observe the results.
Step 3. Make Your Own Angle
Use the MOVE tool to click off all of the recipe steps and clear the work-space.
Use the NEW POINT tool and the RAY THROUGH TWO POINTS tool to create your own angle by following the instructions in the recipe steps.