Around your space
- (d) _l_ (d') when their angle = 90
- if (d) _l_ (d') any line // to one is _l_ to the other
- a st. line (d) is _l_ to plane (p) if and only if it is _l_ to 2 int st lines contained in (p)
- 2 planes are _l_ if their angle= 90
- through a given pt one and only one st line can be drawn _l_ to a given plane
- if (d) _l_ to plane (p) then (d)_l_(a) any line in (p)
How to get an angle ?
- angle of a st line and a plane : The acute angle of a plane (p) and a st line (R) is the angle HIA where h is the the orthogonal proj of any pt A of (R) on (p)
What is the mediator plane ?
Mediator plane of [AB] plane _l_ to [AB] at its midpt
- Any pt of mediator plane is equidistant from extremeties