###
line segment

can be measured because it has 2 endpoints

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congruent

when segments have the same measure

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segment bisector

any segment, line, or plane that intersects a segment at its midpoint

###
perpendicular

lines, segments, or rays that form right angles

###
undefined terms

terms only explained using examples and descriptions

ex: point, line, plane

###
line

made up of points and has no thickness or width

###
collinear

points on the same line

###
plane

flat surface made up of points

###
coplanar

points that lie on the same plane

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space

a boundless, 3D set of all points

contains lines and planes

###
precision

depends on the smallest unit available on the measuring tool

###
between

for any 2 points A and B on a line, there is another point C between A and B

###
constructions

methods of creating geometric figures without the benefit of measuring tools

###
absolute error

the absolute value of the difference between the actual measure of an object and the allowable measure

###
relative error

the ratio of the absolute error to the actual measure

###
significant digits

represent the accuracy of a measurement

###
midpoint

the point on the segment that divides the segment into 2 congruent segments

###
degree

a unit of measure used in measuring angles and arcs

###
opposite rays

if you choose a point on a line, that point determines exactly 2 rays

###
angle

formed by 2 noncollinear rays that have a common endpoint

###
sides

the rays of the angle

###
vertex

the common endpoint

###
exterior

outside an angle

###
acute angle

less than 90 degrees

###
obtuse angle

larger than 90 degrees

###
angle bisector

a ray that divides an angle into 2 congruent angles

###
adjacent angles

2 angles that lie in the same plane, have a common vertex and a common side, but no common interior points

###
vertical angles

2 nonadjacent angles formed by 2 intersecting lines

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linear pair

a pair of adjacent angles with noncommon sides that are opposite rays

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complementary angles

2 angles with measures that have a sum of 90

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supplementary angles

2 angles with measures that have a sum of 180

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n-gon

a polygon with n sides

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regular polygon

a convex polygon in which all the sides are congruent and all the angles are congruent

###
perimeter

the sum of the length of the sides of the polygon

###
circumference

the distance around the circle

###
area

the # of the square units needed to cover a surface

###
polyhedron

a solid with all flar surfaces that enclose a single region of space

###
face

each flat surface (polygon)

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edges

the line segments where the faces intersect

###
prism

a polyhedron with 2 parallel congruent faces

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bases

2 parallel congruent faces

###
regular prism

a prism with bases that are regular polygons

###
pyramid

a polyhedron with all faces except for one intersecting at one vertex

###
regular polyhedron

a polyhedron if all its faces are regular congruent polygon and all of the edges are congruent

###
platonic solids

5 types of regular polyhedra

###
cylinder

a solid with congruent circular bases in a pair of parallel

###
cone

a circular base and a vertex

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sphere

a set of points in space that are a given distance from a given point

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surface area

the sum of the areas of each face of a solid

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volume

the measure of the amount of space the solid encloses

###
orthographic drawing

the 2D views of the top, left, front, and right sides of an object

###
net

a pattern for a 3D solid

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