Geometry Unit 1

Point

-location in space

-no size, shape, length, or width

-0-dimensional

-A, point A, pt. A

line

-Extends forever

-infinite many points

-not measurable

-no, with, length, or thickness

-1 dimensional

-named by any 2 points on the line or a lowercase cursive letter

plane

-flat unbounded surface

-Extends indefinitely

-Infinite amount of points

-2-Dimensional

-Named by 3 non-collinear points on the plane or an uppercase cursive letter (Plane ABC)

line segment

-Part of a line bounded by 2 end points

-has a length that can be measured

-1-dimensional

-named by its two end points

endpoint

-Point at the beginning or end of a line segment

-Point at the beginning of a ray

-0 Dimensional

-Named by capital letter

collinear

-points that are on the same line

-any two points are make a line & are collinear

Non-colinear

-points that are not on the same line

-need to list three points

co-planar

-points that are in the same plane

-must list at least 3 noncollinear points

nonplanar

-points not on the same plane

-must name at least 4 noncollinear points

concurrent

-Lines that contain the same point

Ray

-part of a line that starts at an end point & extends endlessly in 1 Direction

-named by its end point & any other point on that ray

-Symbol always points to the right

-1-dimensional

opposite rays

-two rays that have a common end point & go in opposite directions to form a line

-only intersection is the endpoint

angles

-formed by two rays with a common end point

-vertex: common end point

-sides of the angle: rays

-named by using three letters & middle one must be vertex

-$m<$ = measure of an angle

Polygon

-bounded by line segments & lies in a plane

-2-dimensional

-triangle: Smallest polygon

polyhedron

-bounded by polygons & exists in space

-3-dimensional

-Plural: Polyhedra

greek names

convex

-A polygon where all diagonals are on the inside

concave

-caves In

-at least one diagonal on the outside

regular polygon

-convex polygon were all sides and angles are equal

-equilateral and equiangular

irregular polygon

-sides are not equal & angles are not equal

perimeter

-sum of the lengths of its sides

-square: 4s

-rectangle 2l+2w

Area

-Surface included within a set of lines

-Measured in square units

-square $s^2$

-rectangle: lw

constructions

-Geometric drawings made with only a straight edge and compass

-straight edge: used to draw lines and segments (no measurement)

-compass: Used to draw circles in arcs

bisect

-two divide into two equal parts