第八讲 垂直问题 Lesson 8: Perpendicularity
如果直线垂直于平面内的任意两条
相交直线,则与该平面垂直。反之,如果
直线与平面垂直,则与平面内的任意直线
垂直。 A line is perpendicular to a plane if it is perpendicular to
at least two nonparallel lines in a plane. Also, a line perpendicular to
all lines in a plane if it is perpendicular to that plane.
要讨论的问题 Problems to be solved :
● 过点作直线与平面垂直。
Construct line through a given point perpendicular to a plane.
● 过点作平面与直线垂直。
Construct plane through a given point perpendicular to a line.
一、直线与平面垂直 Perpendicularity of line and plane