Point
An exact location on a line, in a plane or in a space.
Line
A straight path of many points that goes on forever in two directions.
Line Segment
A part of a line that has two end points.
![card image](http://www.onlinemathlearning.com/image-files/basic-geometry-ray-1.gif)
Ray
A part of a line that goes on forever in one direction.
![card image](http://img.tfd.com/wn/CC/6519D-plane-geometry.gif)
Plane
A flat surface of points that goes on in all directions and is named by three points.
![card image](http://www.analyzemath.com/Geometry/angle_1.gif)
Angle
Two rays with the same end point.
![card image](http://www.lawrencegoetz.com/protrac.gif)
Protractor
A tool used to measure angles.
*
Degree
The unit used to measure the size of an angel.
![card image](http://www.analyzemath.com/Geometry/angle_2.gif)
Right Angle
An angel that measures 90* and forms a square corner.
![card image](http://www.analyzemath.com/Geometry/angle_3.gif)
Acute Angle
An angle that measures less than 90* (cute!)
![card image](http://www.analyzemath.com/Geometry/angle_4.gif)
Obtuse Angle
An angle that measures more than 90* (fat!)
![card image](http://www.mathsisfun.com/geometry/images/straight-angle.gif)
Straight Angle
An angle that measures exactly 180* (line)
![card image](http://www.ricksmath.com/images/lines1.gif)
Intersecting Lines
Lines that cross each other to form 4 angles.
![card image](http://www.mathatube.com/images/f-108.gif)
Parallel Lines
Lines in a plane that never intersect and are ALWAYS the same distance apart.
![card image](http://www.icoachmath.com/image_md/Parallel%20and%20Perpendicular%20Lines3.gif)
Perpendicular Lines
Lines in a plane that meet and form a RIGHT angle.
Vertex
The point at which two rays meet to form an angle.
![card image](http://illuminations.nctm.org/lessons/6-8/sorting/Polygons.jpg)
Polygon
A closed plan figure with straight sides.
![card image](http://yoyowhatwhatpeeps.webs.com/photos/Shapes/triangle.gif)
Triangle
A polygon with three sides.
Quadrilateral
A polygon with four sides.
![card image](http://www.teach-nology.com/worksheets/graphic/neworg/pentagon.gif)
Pentagon
A polygon with five sides.
![card image](http://www.coloringpages7.com/Images/school-coloring-pages/shape-coloring-pages/shape-hexagon-coloring-pages-7-com.gif)
Hexagon
A polygon with six sides.
![card image](http://the.gmcs.k12.nm.us/www/gmcs_the/site/hosting/shapes/octagon.png)
Octagon
A polygon with eight sides.
Regular Polygon
A polygon where all sides and angles are equal.
![card image](http://intmstat.com/vectors/irregular-polygon.gif)
Irregular Polygon
A polygon where all angles and sides are not equal.
![card image](http://www.onlineconversion.com/images/shape_area_equilateral_triangle.png)
Equilateral Triangle
A triangle with three equal sides.
![card image](http://nrich.maths.org/content/id/2751/icon.png)
Isosceles Triangle
A triangle with three equal sides.
![card image](http://www.onlineconversion.com/images/shape_area_scalene_triangle.png)
Scalene Triangle
A triangle with no equal length sides.
![card image](http://upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Rtriangle.svg/220px-Rtriangle.svg.png)
Right Triangle
A triangle with one right angle.
![card image](http://www.northstarmath.com/sitemap/images/acute-tri_1.gif)
Acute Triangle
A triangle with 3 acute angles.
![card image](http://www.mathwarehouse.com/geometry/triangles/images/obtuse-triangles/obtuse-triangle-image.gif)
Obtuse Triangle
A triangle with 1 obtuse angle.
![card image](http://www.karenfayeth.com/trapezoid.jpg)
Trapezoid
A quadrilateral with exactly one pair of parallel lines.
![card image](http://amutahush.files.wordpress.com/2009/01/blank-venn-diagram.jpg?w=423&h=289)
Venn Diagram
A diagram that shows relationships (how things are the same and different) between things.
![card image](http://illuminations.nctm.org/lessons/3-5/geometryart/linesofsymmetry.jpg)
Line Symmetry
What a figure has if it can be folded along a line so that both sides match perfectly.
![card image](http://dev.physicslab.org/img/a3f12207-11e5-43ac-b269-aa5346c6e655.gif)
Rotational Symmetry
What a figure has if it can be turned around a central point and still look the same in two positions.
![card image](http://www.freemathhelp.com/images/lessons/congruent-4.gif)
Congruent
Having the same size and shape.
![card image](http://www.k12handhelds.com/data/samples/geometry/img/similar.png)
Similar
Having the same shape but different size.
(7,6)
Ordered Pair
Two numbers that are used to locate a point on a coordinate grid.
X-Axis
The horizontal line on a coordinate grid. (like a bed)
Y-Axis
The vertical side of a coordinate grid. (Think, a pillar)
X-Coordinate
The first number in an ordered pair.
Y-Coordinate
The second number in an ordered pair.
Area
The space inside of a shape. It is measured in square units. The formula is a= l x w (area = length x width)
Perimeter
The the sum of all of the sides.
![card image](http://the.gmcs.k12.nm.us/www/gmcs_the/site/hosting/shapes/cone.gif)
Cone
a solid, pointed figure that has a flat round base.
![card image](http://i.infopls.com/images/tv/printables/botr/botr_098_48-48.gif)
Coordinate Grid
A grid formed by a horizontal line called the x-axis and a vertical line called the y-axis.
Cube
A solid figure with six congruent square faces
Cylinder
A solid figure that is shaped like a can.
Edge
The line segment where two or more faces of a solid figure meet.
Face
A polygon that is the flat surface of a solid figure.
Net
A two-dimensional (flat) pattern that can be foled to make a three-dimensional figure.
Open figure
A figure that does not begin and end at the same point.
![card image](http://upload.wikimedia.org/wikipedia/commons/thumb/9/91/Pyramid.svg/240px-Pyramid.svg.png)
Square Pyramid
A solid figure with a square base and four triangular sides that meet at a single point.
![card image](http://3.bp.blogspot.com/-QQK3zV_Ous4/TdOtGWKA3HI/AAAAAAAAApM/JZ0k18UWB_M/s1600/rectangular+prism.gif)
Rectangular Prism
A solid figure in which all six faces are rectangles.
![card image](http://www.svgopen.org/2008/papers/86-Achieving_3D_Effects_with_SVG/figure_1_sphere_object_with_a_virtual_lighting_source_effect.png)
Sphere
A round object whose curved surface is the same distance from the center to all its points.
![card image](http://www.necompact.org/ea/gle_support/Math/resources_geometry/images/tri_prism.gif)
Triangular Prism
A solid figure that has two triangular bases and three rectangular bases.