1-1 Points lines and planes

1-1 Points lines and planes

Postulate

• Statement of fact, basic building block of logical systems in geometry.

Point

Indicates a location and has no size

Opposite rays

Two rays that share the same endpoint and form a line

Ray

Part of a line that consists of one endpoint and all the points of the line on one side of the endpoint.

Segment

Part of a line that consists of two endpoints and all points between them; middle is midpoint.

Coplanar

Points and lines that lie in the same plane

Collinear Points

Points that lie on the same line

Plane

Represented by a flat surface that extends without end and has no thickness; contains infinitely many lines.

Line

A straight path that extends in two opposite directions without end and has no thickness; contains infinitely many points.

Opposite Rays, AKA...

Line

Postulate 1-1

Through any two points there is exactly one line.

Intersection

A set of points two or more geometric figures have in common

Postulate 1-2

If two distinct lines intersect, then they intersect in exactly one point.

Postulate 1-3

If two distinct planes intersect, then they intersect in exactly one line.

Postulate 1-4

Through any three noncollinear points there is exactly one plane.