1.1 Line Segments , Distance, and Midpoint

1.1a: Definition of Points, Lines and Line Segments 1.1Line Segments, Distance, and Midpoint G-CO.1 Know precise definitions of line segment, based on the undefined notions of point, line, and distance along a line. G-CO.12 Make formal geometric constructions with a variety of tools and methods (compass and straightedge, string, reflective devices, paper folding, dynamic geometric software, etc.). Copying a segment; bisecting a segment; and constructing a line parallel to a given line through a point not on the line CC Standard:

Quadrants (+,+) (-, +) (-,-) (+,-) Origin- where the x and y axis meet (0,0)

Ex. A Graph the points: A ( 2,3) B (-1,2) C( -3, -3) D (0, -2) B D C

Horizontal Lines

Vertical Lines

Ex. • Find the missing Coordinates D ( ) -3 , 2 A(5,2) C ( -3, -4) B( , ) 5 -4

Ex 2. W ( -4 , 7 ) R ( ) 6 , 7 S ( 6 , -8 ) P ( ) -4 , -8

Point 1. Has no dimension (no length, width, thickness) 2. Usually represented by a dot 3. Named using one capital letter • B 4. If a coordinate point B(x, y)

Line • Extends forever in one dimension (length) • Has an arrowhead on each end representing the fact that it goes on forever • Consists of an infinite amount of points • Always straight • Named with a lowercase script letter or by 2 points on the line Can be called: Line l Line AB or AB Line BA or BA l A B

Example of a line • Name the line AD as many ways possible

Definitions • – Collinear Points • Coplanar points – Points that lie on the same line points that lie on the same plane

Plane • Extends forever in 2 dimensions (length & width) • Usually represented by a 4-sided figure • Named with a capital script letter or 3 non-collinear points on the surface of the plane Can be named: 1)Plane W or 2)Plane ABC, plane BCA, plane CBA, etc. W A C B

When 2 planes intersect, their intersection is a … Line • Name the intersection of Plane P and Plane R • Line AB or BH

When a line intersects a plane, their intersection is a … Point Name the intersection of line m with the plane W

Line Segment (or segment) • A section of a line that has 2 endpoints • Named by its endpoints. AB or BA • Order doesn’t matter with segments A B

How many line segments make up this graph? Name Them T A B G

Notation Point •A Line Line Segment Distance between A and B A, Coordinate A(x, y) AB

What is the difference between and AB ?

Problems to complete • In class assignment: 1.1a. Worksheet – Points, Lines, and Line Segments • Homework:

1.1 Line Segments , Distance, and Midpoint