# Shared Flashcard Set

## Details

Geometry Chapter 1
Elena Negron
39
Mathematics
10/18/2012

Term
 Point
Definition
 A point specifies only location; it has no length, width, or depth. We usually represent a point with a dot on paper, but the dot we make has some dimension, while a true point has dimension 0. [image]
Term
 Line Segment
Definition
 A line segment is the portion of a line lying strictly between two points. It has a finite length and no width. [image]
Term
 Ray
Definition
 A ray can be thought of as a half a line. It has a point on one end, and it extends infinitely in the other direction. [image]
Term
 Plane
Definition
 A plane is a flat, two-dimensional object. We often represent a plane by a piece of paper, a blackboard, or the top of a desk. In fact, none of these is actually a plane, because a plane must continue infinitely in all directions and have no thickness at all. A plane can be defined by two intersecting lines or by three non-collinear points.

[image]

Term
 Collinear
Definition
 lying in the same straight line. [image]
Term
 Opposite Rays
Definition
 Two rays with a common endpoint that point in opposite directions and form a straight line. [image]
Term
 Coplanar
Definition
 In the same plane.  [image]
Term
 Angle
Definition
 A shape, formed by two lines or rays diverging from a common point (the vertex) [image]
Term
 Midpoint
Definition
 A point on a line segment that divides it into two equal partsThe halfway point of a line segment [image]
Term
 Bisector
Definition
 A line which cuts an angle into two equal halves [image]
Term
 Congruent
Definition
 Two figures are congruent if all corresponding lengths are the same, and if all corresponding angles have the same measure. Colloquially, we say they "are the same size and shape," though they may have different orientation. (One might be rotated or flipped compared to the other.) [image]
Term
 Vertex
Definition
 A vertex is the point where two sides of a polygon meet. [image]
Term
 Acute Angles
Definition
 A positive angle that measures less than 90° [image]
Term
 Obtuse Angles
Definition
 An angle whose measure is greater than 90° and less than 180° [image]
Term
 Right Angle
Definition
 An angle whose measure is exactly 90° [image]
Term
 Straight angle
Definition
 An angle whose measure is exactly 180° - a straight line [image]
Term
 Complementary angles
Definition
 Two Angles are Complementary if they add up to 90 degrees (a Right Angle) [image]
Term
 Supplementary angles
Definition
 Two angles that add up to 180° [image]
Term
 Vertical angles
Definition
 Vertical Angles are the angles opposite each other when two lines cross. [image]
Term
Definition
 Two angles are Adjacent if they have a common side and a common vertex (corner point) and don't overlap. [image]
Term
 Linear pair
Definition
 Two angles that are adjacent (share a leg) and supplementary (add up to 180°) [image]
Term
 Perpendicular lines
Definition
 A line is perpendicular to another if it meets or crosses it at right angles (90°). [image]
Term
 Polygon
Definition

A polygon is a two-dimensional geometric figure with these characteristics:

 • It is made of straight line segments. • Each segment touches exactly two other segments, one at each of its endpoints. • It is closed -- it divides the plane into two distinct regions, one inside and the other outside the polygon.

[image]

Term
 Triangle
Definition
 A closed figure consisting of three line segments linked end-to-end. A 3-sided polygon. [image]
Term
Definition
 Quadrilateral just means "four sides" (quad means four, lateral means side). [image]
Term
 Pentagon
Definition
 A polygon with 5 sides [image]
Term
 Hexagon
Definition
 A polygon with 6 sides [image]
Term
 Octagon
Definition
 A plane figure with eight straight sides and eight angles. [image]
Term
 Decagon
Definition
 A plane figure with ten straight sides and angles. [image]
Term
 Dodecagon
Definition
 A plane figure with twelve sides. [image]
Term
 N-gon
Definition
 A closed plane figure bounded by three or more line segments. [image]
Term
 Concave
Definition
 Having an outline or surface that curves inward like the interior of a circle or sphere. [image]
Term
 Convex
Definition
 Having an outline or surface curved like the exterior of a circle or sphere. [image]
Term
 Regular
Definition
 a polygon with all sides and all angles equal

[image]

Term
 Irregular
Definition
 A polygon that does not have all sides equal and all angles equal. A polygon is "regular" only if all angles are equal and all sides are equal otherwise it is irregular. [image]
Term
 Diagonal
Definition
 (of a straight line) Joining two opposite corners of a square, rectangle, or other straight-sided shape. [image]
Term
 Side
Definition
 One of the lines that make a flat (2-dimensional) shape.Or one of the surfaces that make a solid (3-dimensional) object. [image]
Term
 Perimeter
Definition
 The distance around a two-dimensional shape.Example: the perimeter of this rectangle is 3+7+3+7 = 20The perimeter of a circle is called the circumference. [image]
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