Google Classroom
GeoGebraGeoGebra Classroom

Line Perpendicular to Plane 垂直於平面的直線

Move point A such that AB is perpendicular to the plane. Then move point D. Does angle ABD change? 移動A點使AB垂直於平面。然後移動D點。角ABD有變化嗎?
GeoGebra 互動數學教室 http://www.geogebra.hk