Points, Lines & Planes

Chapter 1-2

Point

• A point has no dimension.• It is represented by a dot.• It is named by a capital letter.

A

Line• A line has one dimension.• It is a series of points that extends in 2

directions without end. A line has arrowheads on each side to show it continues on and on.

• You can use any 2 points on a line to name it.

Collinear

• Points that lie on the same line are COLLINEAR.

Plane• A plane has two dimensions.• It is a flat surface that extends in all directions

without end, but it has no thickness.• You can name a plane either by using a capital

letter or by naming 3 noncollinear points in the plane.

Coplanar

• Points and/or lines on the same plane are coplanar.

Are you ready for some football?

Postulate• An accepted statement of FACT.

Postulate 1-1

• Through any two points there is exactly one line.

• Line l is the only line that can pass through points A and B.

Postulate 1-2

• IF two lines intersect, then they intersect at exactly one point.

Postulate 1-3• If two planes intersect, they intersect in a line.

Postulate 1-4

• Through any three noncollinear points, there is exactly one plane.