1.2 Points, Lines and Planes Postulate or axiom – an accepted statement of fact. These are the basic building blocks of Geometry

There are 3 undefined terms in Geometry: They are only explained by using examples and descriptions. Point: P P Description: a point indicates a location and has no size

Line: Named by 1) 2) Points on the same line are said to be Points not on the same line are said to be **Through any 2 points there is exactly RS The intersection of two lines is at a _______________. AB CD E Any two points on the line A single lowercase letter Collinear noncollinear One line point Straight path that extends in two opposite directions without end

*Through any 3 noncollinear points there is exactly ____________________. Points on the same plane are said to be Points not on the same plane are said to be Plane: Named by 1) 2) M A B C The intersection of two planes is at a _______________. A flat surface that extends without end. Capital letter At least three points that do not all lie on the same line one plane Coplanar noncoplanar line

Space : When drawing 3-dimensional pictures use dashed lines to represent the parts of the picture that you cannot see. How many planes are shown in the figure? Name 3 collinear points. Name 3 coplanar points. J E I C A D HG F B The set of all points in three dimensions

Line Segment : PQ with no symbol above it means QP Part of a line that consists of two endpoints and all points between them Length of

Ray: RPQ AB Part of a line that consists of one endpoint and all the points of the line on one side of the endpoint

Any point on a line divides the line into 2 rays called ___________________. Collinear rays with a common endpoint, extending in opposite directions. CDE Opposite rays

PWS 1-2 #’s 1-29