Numbers and Angles
Numbers
You can create numbers by using the Input Bar. If you only type in a number (e.g. 3), GeoGebra assigns a lower case letter as the name of the number. If you want to give your number a specific name, you can type in the name followed by an equal sign and the number (e.g. create a decimal r by typing in r = 5.32).
You can also use the constant π and the Euler constant e for expressions and calculations by selecting them from the drop down list next to the Input Bar or by using Keyboard Shortcuts.
Angles
Angles are entered in degree (°) or radians (rad). The constant π is useful for radian values and can also be entered as pi.
- Alt + O (Mac OS: Ctrl + O) for the degree symbol °
- Alt + P (Mac OS: Ctrl + P) for the pi symbol π
- If a = 30 is a number, then α = a° converts number a to an angle α = 30°, without changing its value.
- If you type in b = α / °, the angle α is converted back to the number b = 30, without changing its value.
Free Numbers and Angles
Free numbers and angles can be displayed as sliders in the Graphics View (see Slider Tool). Using the arrow keys, you may change the value of numbers and angles in the Algebra View too (see Manual Animation section).
Limit Value to Interval
Free numbers and angles may be limited to an interval [min, max] by using tab Slider of the Properties Dialog (see also Slider Tool).