53 terms

# Chapter 9 pre algebra geometry

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Circumference
Distance around circle
Diameter
A chord that passes through the center of the circle
Segment that has one endpoint at the center and the other point on the circle
Circle
The set of all points in a plane that are the same distance apart
Alternate interior angles
Non-adjecent interior angles that lie on the same side of the transversal
Corresponding angles
lie on the same side of the transversal and are in corresponding positions
Plane
flat surface with no thickness that contains many lines and extends without end in the direction of all its lines

ABCD
Point
location in space with no size
Line
series of points that extends in opposite directions with no end
<-> <->
AB BA
Line segment
Part of a line with 2 endpoints

___ ___
PQ QP
Ray
Part of a line that has exactly one endpoint

<->
CR
Parallel
Two lines that lie in the same plane and dont intersect
Skew
Lines that are in the same plane and dont intersect and aren't parallel
Acute
less than 90º angle
Obtuse
Greater than 90º and less than 180º
Right angle
90º angle
Straight angle
equal to 180º
straight line
Share and vertex and a side but no common points
Vertical
formed by two intersecting lines and are opposite
Congruent
Angles that have the same measure
Supplementary
sum of two angles is 180º
Complementary
sum of two angles is 90º
Transversal
Lines that intersect two other lines in different points
Corresponding
Lie on the same side of the transversal and corresponding
Polygon
closed plane figure with at least three sides that only meet at their endpoint
Triangle
three sided polygon
Acute triangle
3 acute angles
Right triangle
1 right angle
Obtuse triangle
1 obtuse angle
Equilateral
3 congruent sides
Isosceles triangle
2 congruent sides
Scalene triangle
no congruent sides
4 sides
Trapezoid
At least one pair of parallel sides
Paralellogram
both pairs of opposite sides are parallel
Rhombus
four congruent sides
Rectangle
four 90º angles
square
four 90º angles and four congruent sides
Regular polygon
all sides and angles congruent
Pentagon
5
Hexagon
6
Heptagon
7
Octagon
8
Nonagon
9
Decagon
10
Chord
segment whose endpoints are in a circle
formula for circumference
c=πd
c=πr2

c=circumference
d=diameter
2=2x
π=pi
Central angle
angle whose vertex is the center of a circle
360º in a circle
Perpendicular lines
lines, segments, or rays that intersect to form right angles
segment bisector
lines, segments, or rays that divides a segment into two congruent segments
perpendicular bisector
lines, segments, or rays that is perpendicular to the segment in bisects
Angle bisector
ray that divides an angle into two congruent angles
pi
3.1415....etc
π