You need to install ActiveX plug-in to be able to view this model.
Construct an angle equal to a given one. The angle should be protracted to the upper half-plane of the given ray.
Solve the problem alone and verify your solution by using the "Verify" button. The result will not be registered. If you want to watch the video clip including the problem solution, click the "Motion video" button in the suitable theory section.
You can download it here.