GeometryGeometry

Chapter 1-1Chapter 1-1

Why do chairs sometimes wobble?Why do chairs sometimes wobble?

What do the feet of a three legged stool What do the feet of a three legged stool represent?represent?– Points that lie in the same plane.Points that lie in the same plane.

Why does a four legged chair sometimes Why does a four legged chair sometimes wobble on a flat surface?wobble on a flat surface?– One of the legs represents a point that doesn’t One of the legs represents a point that doesn’t

lie in the same plane as the other 3.lie in the same plane as the other 3.

Key TermsKey Terms

A A pointpoint is simply a location is simply a location

A A lineline is made up of points that has no is made up of points that has no thickness or width.thickness or width.– Points that are on the same line are said to be Points that are on the same line are said to be collinearcollinear..

Terms cont…Terms cont…

A A planeplane is a flat surface made up of points. is a flat surface made up of points. Points that lie on the same plane are said to Points that lie on the same plane are said to

be be coplanarcoplanar.. A A planeplane has no depth and extends infinitely has no depth and extends infinitely

in all directions.in all directions.

PointsPoints are often used to name are often used to name lineslines and and planes.planes.