includes points, lines, rays, angles, polygons, triangles, quadrilaterals, circles

###
point

has no size, only location

###
line

straight, continous arrangement of infinitely many points; has no thickness; one-dimensional

###
plane

flat surface; two-dimensional; surface extends indinitely along its length and width; a plane is named with script capital letter

###
collinear

points that lie along the same line

###
coplainar

points that lie within the same plane

###
line segment

consists of two points called the endpoints of the segment and all the points between them that are collinear with the two points

###
congruent segments

segments that are equal in measure or length

###
midpoint

the point on the segment that is the same distance from both endpoints. A pair of hatch marks refer to line segments being the same length

###
ray

begins at a point and extends infinitely in one direction

###
angle

formed by two rays that share a common endpoint

###
vertex

the common endpoint of the two rays of the angle

###
sides

the rays of an angle

###
measure of an angle

the smallest amount of rotation about the vertex from one ray to the other

###
degrees

unit of measurement for an angle

###
protractor

a geometry tool used to measure angles

###
congruent angles-

angles that are equal in measure

###
angle bisector

a ray that divides the angle into two congruent angles

###
parallel lines

lines that do not intersect and are part of the same plane

###
perpendicular lines

lines that do intersect and form a right angle

###
skew lines

lines that are neither parallel nor do they intersect (for 3-D setting)

###
right angle

an angle that measures 90 degrees

###
acute angle

an angle that measures less than 90 degrees

###
obtuse angle

an angle that measures more that 90 degrees

###
pair of vertical angles

angles that are formed by two intersecting lines; they share a common vertex but not a common side

###
linear pair of angles

two angles are a ____if they share a vertex and a common side and their non-common sides form a line

###
complementary angles

angles that form a right angle

###
supplementary angles

angles that sum up to 180 degrees

###
polygon

closed figure in a plane, formed by connecting line segments endpoint to endpoint with each segment intersecting the other

###
consecutive vertices

vertices that are adjacent to one another

###
consecutive angles

angles that are adjacent to one another

###
diangonal

a line segment that connects any two nonconsecutive vertices

###
concave polygon

a polygon that has at least one diagonal on the outside

###
convex polygon

a polygon that has no diagonals on the outside

###
congruent polygons

polygons that have exactly the same size and shape

###
equilateral polygons

a polygon who's sides are all equal

###
equilangular polygon

a polygon whose angles are all equal

###
regular polygon

a polygon whose sides and angles are all equal

###
icosakaihenadecagon

21 sides

###
chiliagon

1000 sides (chilagon?)

###
acute triangle

all angles are less than 90 degrees

###
obtuse triangle

one angle is more than 90 degrees and less than 180 degrees of a three sided polygon

###
right triangle

one angle is exactly 90 degrees

###
scalene triangle

no two sides are congruent of a three sided polygon

###
isosceles triangle

at least two sides are congruent of a three sided polygon

###
equilateral triangle

all sides are congruent of a three sided polygon

###
trapazoid

a quadrilateral with exactly one pair of parallel sides

###
isosceles trapazoid

top and bottom are parallel, two sides are congruent, top two angles are congruent, bottom two angles are congruent

###
right trapazoid

two right angles

###
kite

a quadrilateral with two pairs of consecutive congruent sides. The diagonails are perpendicular

###
parallelogram

a quadrilateral with two pairs of parallel sides

###
rhombus

an equilateral parallelogram

###
rectangle

a parallelogram with four congruent angles (right angles); an equilateral parallelogram

###
square

an equilateral, equilangular parallelogram; a regular quadrilateral; an equalateral rectangle

###
circle

a set of all points in a plane that are the same distance from a given point (center) in a plane

###
radius

a line segment from the center point of a circle to a point on the edge of a circle

###
diameter

a line segment passing through the center point of a circle and whose endpoints are on the edge of the circle

###
chord

any line segment whose endpoints are on the edge of a circle; the diameter is the longest chord

###
congruent circles

circles that have the same radius length

###
concentric circles

circles that share the same center point

###
arc of a circle

the continuous (unbroken) part of a circle that is in between two points on the edge of a circle

###
semicircle

arc of a circle whose endpoints are the endpoints of the diameter

###
minor arc

an arc of a circle that is smaller than a semicircle

###
major arc

an arc of a circle that is larger than a semicircle

###
arc measure

the measure of the central angle (in degrees)

###
central angle

angle formed by two radii and whose vertex is the center point of a circle

###
tangent

a line that intersects the circle at exactly one point

###
secant

a line that intersects the circle at exactly two points

###
inscribe angle

angle whose vertex is the point on a circle; the sides of this angle are the chords of the circle