###
line segment

can be measured because it has 2 endpoints

###
congruent

when segments have the same measure

###
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

###
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

###
linear pair

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

###
complementary angles

2 angles with measures that have a sum of 90

###
supplementary angles

2 angles with measures that have a sum of 180

###
n-gon

a polygon with n sides

###
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)

###
edges

the line segments where the faces intersect

###
prism

a polyhedron with 2 parallel congruent faces

###
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

###
sphere

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

###
surface area

the sum of the areas of each face of a solid

###
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

### Please allow access to your computer’s microphone to use Voice Recording.

## We can’t access your microphone!

### Click the icon above to update your browser permissions and try again

Example:

### Reload the page to try again!

Reload

## Press Cmd-0 to reset your zoom

## Press Ctrl-0 to reset your zoom

### It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

## Your microphone is muted

### For help fixing this issue, see this FAQ.