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.