On whiteboard draw the guided practice diagram shown on pg. 7 Reference this diagram as you discuss the terms

1.2 Points, Lines, and Planes

There are three undefined terms in geometry: What is a definition? Known words used to describe a new word Undefined terms – are terms not formally defined. There are three undefined terms in geometry: 1. Point 2. Line 3. Plane

Point 1. A location in space. 2. Has no dimension (no length, no width, no depth). 3. All geometric figures consist of points POINTS ARE TO GEOMETRIC FIGURES AS ___________ IS TO HUMANS?

What would be a real world example of a point? For example: ●B What would be a real world example of a point?

Line An infinite set of points that extends in opposite directions forever. One-dimensional (length). Always straight.

How do we name a line has more than 2 points on it? For example: Can be called: Line l Line AB or AB Line BA or BA l A B Real World example? How do we name a line has more than 2 points on it?

Plane A flat surface that extends forever in two dimensions (length & width). Contains infinitely many points and lines. Has no thickness

Plane For example: Can be named: Plane W Plane ABC, plane BCA, plane CBA, etc. **Planes can be named by more than 3 points, but they must be named in either a clockwise or counter-clockwise manner A W C B Real World example?

Horizontal Planes – Ceiling and Floor Horizontal Planes – Two sides horizontal and no sides vertical 10

Vertical Planes – Walls Vertical Planes – two sides are vertical 11

**Think of the preffix “CO” as sharing.** More Definitions Collinear points – points that can lie on the same line. **Think of the preffix “CO” as sharing.**

More Definitions Noncollinear points – D

More Definitions Coplanar points – What does it mean? points that can lie on the same plane.

More Definitions If the points do not lie in the same plane they are? Noncoplanar points – A D

QUESTIONS 1 – 10 ON WORKSHEET 16

More Definitions Intersect – Intersection – Two or more figures intersect if they have one or more points in common. Think “meet” or “Cut” Intersection – All points or sets of points the figures have in common. Depending on what is intersecting, the intersection will be different

4 types of intersections between points, lines, and planes Point and a line 2 lines 2 planes A plane and a line

When a line and a point intersect, their intersection is a point. B Like taking a road trip and driving through a certain town or city on the map.

When 2 lines intersect, their intersection is a point. Like the intersection of Foothill and Ramsdale

When 2 planes intersect, their intersection is a line. The planes are cutting through one another

When a line and plane intersect, their intersection is a point. Like sticking a pencil through a piece of paper

QUESTIONS 11 - 14

More Definitions Equidistant – equally distant

TRUE/FALSE PF ends at P A plane has no thickness REST OF QUESTIONS

Questions???