A plane is determined by
- 3 non-collinear points
- A line and a point outside the plane
- 2 intersecting lines
- 2 parallel lines
How to prove a line perpendicular to a plane ?
If a straight line is perpendicular to 2 intersecting lines in a plane then its perpendicular to the plane itself.
When Is a Line Perpendicular to a Plane? : Trigonometry & Other Math
Relative position of a plane and a line :
- The line is in the plane
Relative position of 2 lines :
How to prove that 2 planes are perpendicular ?
Relative position of 2 planes :
Angle between 2 planes - Dihedral angle
The Steps :
1- Find the common line.
2- Select 2 lines perpendicular from each plane to the common line.
3- Find the angle.
Property : Any point on the mediator plane of a line is equidistant from the extremities of this line.
How to prove a mediator plane to a line ?
Prove that it has 3 points equidistant from the extremities of the line.
How to prove 3 collinear points?
Prove that they belong to a line that is the intersection of 2 planes