[b](Updated: 8 Sept 2016)[/b][br]Measure the angle using the protractor.[br]Drag the protractor to appropriate position, use the red point to rotate it if necessary.[br]Drag the green points or press the "New Angle" button to change the angle.[br]Enter the angle measure in the input box (backspace to delete the ? first).

Edited by Celia Jimenez from Anthony Or. GeoGebra Institute of Hong Kong.