Suzanne Chludzinski ILS The Basic Elements of Geometry

Building Blocks of Geometry Everything in Geometry is made of the following three basic elements. 1.Point 2.Line 3.Plane

Point Has no size Only has location Represented with a dot Named with a capital letter A Point A

Line Straight continuous arrangement of infinitely many points Extends forever in two directions Represented by a line with arrows on each end Named by giving any two points on the line or a lower case letter. j Line j A B Line AB

Plane Has length and width but no thickness Similar to a flat surface that extends forever along its width and length Represented with a four sided figure and a capital letter in the lower left corner. Named with a capital letter. P Plane P

Types of Lines Intersecting: lines that meet in one point. –Perpendicular lines Non-intersecting: lines that never meet –Parallel –Skew

Perpendicular Lines Definition: Lines that intersect at a 90 degree angle. 90 degrees

Examples of Perpendicular Lines Street Intersections Crosswalks

Parallel Lines Definition: Lines that are in the same plane that never intersect.

Examples of Parallel Lines Railroad Tracks Yellow Street Lines

Skew Lines Definition: Lines that are in different planes and never intersect