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

What is a definition? Known words used to describe a new word Known words used to describe a new word Undefined terms – are terms not formally defined. There are three undefined terms in geometry: 1. Point2. Line3. 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? POINTS ARE TO GEOMETRIC FIGURES AS ___________ IS TO HUMANS?

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

Line 1. An infinite set of points that extends in opposite directions forever. 2. One-dimensional (length). 3. Always straight.

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

Plane 1. A flat surface that extends forever in two dimensions (length & width). 2. Contains infinitely many points and lines. 3. Has no thickness

Plane A B C W 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 For example: Real World example?

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

Vertical Planes – Walls Vertical Planes – two sides are vertical

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

More Definitions Noncollinear points – Noncollinear points – D

More Definitions Coplanar points – What does it mean? 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? If the points do not lie in the same plane they are? Noncoplanar points – Noncoplanar points – D A

QUESTIONS 1 – 10 ON WORKSHEET

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

1. Point and a line 2. 2 lines 3. 2 planes 4. A plane and a line 4 types of intersections between points, lines, and planes

When a line and a point intersect, their intersection is a point. B l 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

More Definitions Equidistant – equally distant Equidistant – equally distant

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

Questions???