Plane Geometry Unit 1 – Chapter 1 Section 1.1 – Identify Points, Lines, and Planes Day 1

l Section 1.1 Notes P A B C LINE NOTATION: Undefined Terms – Vocabulary without a formal definition, but overall agreement with what the term means. Point – representation of a unique location in space. It has no dimension. Line – connection of an infinite number of points. It has one dimension. P l A B C LINE NOTATION: Line l, Line AB ( AB ), Line ( BC ), or Line AC ( AC )

Section 1.1 Notes AB A B A B AB A B AB RAY NOTATION: Compare and Contrast: Line – Infinite in length, extends endlessly in opposite directions. Segment – Finite portion of a line that begins and ends at endpoints (points on that line). Ray – Infinitely long portion of a line that begins at an initial point and extends endlessly in one direction. AB A B A B AB Endpoint A B AB RAY NOTATION: Point with no arrow head is called endpoint, always list endpoint first and always draw arrow pointing right.

Section 1.1 Notes Extension: Opposite Rays – two rays that share the same endpoint but extend in exactly opposite directions. They =alwys form a straight line. What are the opposite rays for the image given? Endpoint A H I HA HI

M Section 1.1 Notes PLANE NOTATION: W Plane – a flat surface that contains an infinite amount of lines and extends endlessly in two directions. M PLANE NOTATION: Plane M, or Plane COW, Plane WOC, Plane OCW W O C PLANE NOTATION: Use any three points that lie on the plane and that do not lie in a line, or if a letter already represents it.

Section 1.1 Notes A B C D H G O S Collinear Points – points that all lie on the same line. Coplanar Points – points that all lie on the same plane. A B C D H G O S

Section 1.1 Notes A Identification, name: The plane: HOD, DOG, DGH A Line: AB, OB, HG, GO, … A Segment: GO, AO, BO, HG, … A Ray: OG, GH, BA, AB, HG, … D H O G B

Section 1.1 Notes E A D C B F Identification, Collinear or not? B, D C, E A, D B, F F, E, D A, E, D D, B, C C, E, F YES NO A D C B F

Section 1.1 Notes E A D C B F Identification, Coplanar or not? B, C, D A, B, C F, E, D E, A, F A, B, C, D F, E, D, C E, A, D, C B, C, D, E, F YES NO A D C B F

Section 1.1 Notes E C O P C M W F Intersections: 2 lines always intersect at a point (Figure 1) A line that does not lie on a plane can intersect a plane at a point. (Figure 2) E C Intersection O Intersection P C M W Figure 1 Figure 2 F

a M Q Section 1.1 Notes Intersections: (cont.) 2 Planes always intersect at a line (Figure 3) a M Q Intersection: Line a Figure 3

CHECK FOR UNDERSTANDING…Time to Draw… Four coplanar points…three or which are collinear. A D C B

CHECK FOR UNDERSTANDING…Time to Draw… Two coplanar lines that do NOT intersect. F E H B C D

CHECK FOR UNDERSTANDING…Time to Draw… Opposite rays AB and AC. Endpoint B A C AB AC

CHECK FOR UNDERSTANDING…Time to Draw… Three planes that do not intersect. B A M

CHECK FOR UNDERSTANDING…Time to Draw… Three coplanar lines that intersect at the same point. B F H E E C D B

CHECK FOR UNDERSTANDING…Time to Draw… Two planes that intersect one another. a M Q

CHECK FOR UNDERSTANDING…Time to Draw… Two lines that intersect and a third line that does not intersect either of them. E A G D C H B F

CHECK FOR UNDERSTANDING…Time to Draw… Three lines that intersect at a point but are not coplanar. A D H O G F B

P. 3-5 #1 – 7 “Guided Practice” CONCEPT CHECK P. 3-5 #1 – 7 “Guided Practice”

HOMEWORK P. 5-6 #3 - 26 (Omit #12)