Fixed angles have no third point, but a fixed size. This type of angle
behaves more like a ray than like an angle. It is possible to
intersect with the ray or place points on it.
Z.u.L. > Documentation > Context Help
Fixed angles have no third point, but a fixed size. This type of angle
behaves more like a ray than like an angle. It is possible to
intersect with the ray or place points on it.
Fixed angles are generated by holding down the Shift-key, while clicking for the third point, or with the special tool for fixed angles. This will open the settings dialog, where the user can enter any expression for the size of the angle. If the angle is dragged immediately, the settings dialog will not open.
Fixed angles can be sized using three given points, or any other expression or angle. To do this select the button "set size ..." in the settings dialog. Then e.g., select three points A, B, C, where B is the corner point. The angle will be the same size as the angle ABC. You can also use any other expression or angle to size the angle.
Fixed angles can be inverted. Thus one does not have to use positive orientation. Furthermore, if a fixed angle is restricted to 180 (which is the default), and if such an angle is constructed in a mathematical negative way, it will be inverted. There is an icon in the settings dialog, which controls the inversion.
Related topics: Circles, Reorder points, Syntax for Expressions, Object Properties, Angles
Next topic: Filled Polygons