36 terms

# Tools of Geometry

Geometry Chapter 1
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acute angle
an angle with a measure greater than 0 degrees and less than 90 degrees
angle
two rays with a common endpoint
angle bisector
A ray that divides an angle into two congruent angles.
area
the number of square units needed to cover a flat surface
circumference
distance around a circle
collinear points
Points that lie on the same line.
complementary angles
Two angles whose measures have the sum of 90 degrees
congruent angles
Angles that have the same measure.
congruent segments
Segments that have the same length
coordinate
The number that corresponds to a point
coplanar
figures in the same plane
line
a series of points that extends in two opposite directions without end
midpoint
a point that divides a segment into two congruent segments
obtuse angle
An angle that measures more than 90 degrees but less than 180 degrees
opposite rays
two collinear rays with the same endpoint
parallel lines
lines in the same plane that never intersect
parallel planes
planes that do not intersect.
perimeter
The sum of the lengths of the sides of a polygon.
perpendicular bisector
a segment, ray, line, or plane that is perpendicular to a segment at its midpoint
perpendicular lines
Two lines that intersect to form right angles
plane
A flat surface that goes on forever in all directions
ray
part of a line with one endpoint
right angle
an angle that measures 90 degrees
segment
part of a line with two endpoints
skew lines
lines that do not lie in the same plane
straight angle
an angle whose measure is 180 degrees
supplementary angles
two angles that add up to 180 degrees
vertical angles
two angles whose sides form two pairs of opposite rays
Midpoint Formula
M = [ ( x₂ + x₁) / 2, (y₂ + y₁) / 2 ]
Distance formula
d = √[( x₂ - x₁)² + (y₂ - y₁)²]

It does not matter which point is labeled 1 and which is labeled 2
Perimeter of a Rectangle
P = 2L+2W
where L = length and W = width
Perimeter of a Square
P = 4s
where s = length of side
Circumference of a Circle
C=2πr or C=πd
where r = radius and d = diameter and π = pi (approx. 3.14)
Area of a Square
A = s²
where s = length of side
Area of a Rectangle
A = L x W
where L=length and W = width
Area of Circle
A=πr²
where r = radius and π = pi (approx. 3.14)

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