WW

points lines and planes

POINT

  • A position on a paper or a position on space, no size

  • - Marked by upper case letter


A B


LINE

  • An infinite number of points

<—--------—---------------------—--------—--------------------->

A B

Arrows indicate the direction of the line

The arrows also show there's no eneding


  • The line can be called AB or BA

<—--------—---------------------—--------—--------------------->


If no point, line will be called line L




Collinear and Non-collinear


Collinear point: Points that lie on the same line


A B C


Non- Collinear point: Points that don’t lie on the same line


B

A C



PLANE: an infinite number of lines

  • Flat surface that extends in all directions


—-—-—-—-—-

|         Q |

| E |

|   F           G |

—-—-—-—-—-

 

-plane Q

Plane FEG

Plane GEF


Coplanar point: Points that lie on the same plane


Line segments: section of line that has specified ends



•—-----------------------------•  - endpoints

G     H


GH or HG



Rays: A line that as fixed starting point, but no end point


•—-----------------------------•----------------------------> GH

G     H




<—-----------------------------•----------------------------• HG

    G     H



Opposite rays: two rays that share the same initial point and extend infinitely in opposite directions along the same line.


  • If point 𝐶 lies on  𝐴𝐵 between 𝐴 and 𝐵, then 𝐶𝐴 and 𝐶𝐵 are opposite rays.

<—--------•—-------------------•--—--------—---------•------------>

    A       C   B






INTERSECTION: One or more points laying on two or more geometric figured



  • An intersection of two distinct line is a point

  • An intersection of two distinct plane is a line