# Untitled

Stuff you need to know to pass Matt's test

## Terms

undefined, object
copy deck
polyhedron
bounded by polygons, exist in space, and is 3 dimensional
exterior angle theorem
an exterior angle of a triangle is greater than either remote interior angle
indirect proof
assume the opposite then prove by contradiction
postulate one
2 point determine a line
obtuse
iff more than 90 but less than 180
deductive reasoning
uses logic to draw conclusion from statements already acccepted as true
line segment
part of a line bounded by 2 endpoints...can be measured
vertical angle theorem
vertical angles are equal
plane
space
betweeness of points theorem
if A-B-C, then AB+BC = AC
if a>b and c>d, then a+c > b+d
ASA postulate
if 2 angles and the included side of one triangle are equal to two angles and the included side of another triandle, the triangles are congruent
division property
if a>b and c>o, then a/c >b/c
deductive system
a logical system of constructing proofs using definitions, postulates and theorems
subtraction property
if a>b, then a-c> b-c
betweeness of rays theorem
if OA-OB-OC, then AOB+BOC = AOC
conditional statement
P-->Q statements..if rain, then wet.
if a>b, then a+c > b+c
theorem 13
if 2 sides of a triangles are unequal then angles opposite them are unequal in the same order
exterior angle
a angle that forms a linear pair with an angle of the trianle
area
number of units squares equal in measure to it's surface
identity
a+0=a do something to make it itself
point
refers to a location on a plane
corollary to congruent
2 triangles congruent to a 3rd triangle are congruent to eachother
SAS postulate
if two sides and the included angle of one triangle are equal to two sides and the included angle of another triangle, the triangles are congruent
betweeness of points
A-B-C iff ab>c
iff
if and only if
inductive reasoning
drawing conclusions through a limited set of observations
SSS theorem
if three sides of one triangle are equal to the three sides of another, the triangles are congruent
theorem
a statement that is proved by reasoning deductively
whole greater than part theorem
if a>0, b>0, and a+b=c, then c>a and c>b
parallel
lie on the same plane but never intersect
division property
if a = b and c is not zero, then a/c = b/c
transitive property
if a>b and b>c, then a>c
triangle inequality theorem
the sum of any 2 sides of a triangle is greater than the third side
non collinear
can never be on the same line
collinear
on the same line
if a=b, then a+c = b+c
commutative
(A+B = B+A) you can switch adding order
substitution property
if a = b, then a can be used for b in any expression
corollary
can be easily proved from a postulate or another theorem
3 possibilities property
either a>b, a
multiplication property
if a>b and c>0, then ac > bc
polygon
a connected set of at least 3 line segments in the same plane such that each segment intersects exactly 2 others
ray
a line that extends from a point and goes on forever in one direction
converse
reversing the conditional statement
inverse
a+(-a)=0 the what you started with the opposite
reflexive property
a=a...any # is equal to itself
ruler postulate
i can use my ruler to measure stuff
multiplication property
if a=b, then ac = bc
theorem 10
if 2 angles of a triangle are equal the sides opposite them are equal
conclusion
Q or the then part
postulate
assumed to be true without proof
postulate 2
3 noncollinear points determine a plane
associative
(a+b)+c=a+(b+c) you can move brackets around
coplanar
points on the same plane
theorem 9
if 2 sides of a triangle are equal the angles opposite them are equal
subtraction property
if a=b, then a-c = b-c
perimeter
sum of all the sides
hypothesis
P or the if part
congruent
if a shape is congruent there is a correspondence between their vertics and all sides are equal and correspond
line
straight, endless arrangement of points going on in both directions
triangle angle sum
sum of all angles equals 180
angle
a pair of rays with the same endpoint
concurrent
lines that contain the same point
theorem 14
if 2 anles of a triangle are unequal, the sides opposite them are unequal in the same order

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