Quiz on Angles in a Circle 圓內的角：測驗
If you find some bugs in this applet, please choose "debug", take a photo and report in http://www.facebook.com/hkgeogebra.
如程式出錯，請勾選「debug」、拍照並到 http://www.facebook.com/hkgeogebra 留言。
gMath 互動數學教室
http://www.gmath.hk