Using Protractor to Measure Angles 以量角器量度角

Demonstrate how to use the protractor to measure an angle.
示範如何以量角器量度角。

English version: http://www.geogebratube.org/material/show/id/2461 (Download GeoGebra file)
中文版:http://www.geogebratube.org/material/show/id/2456 (Download GeoGebra file)

Measure the angle using the protractor.
Drag the protractor to appropriate position. Drag the red point to rotate it.
Drag the green points to adjust the angle.

利用以下的量角器量度所示的角。
將量角器拖拉到合適的位置,拖拉紅點轉動它。
拖拉綠點調整角的位置和大小。