27 terms

# Review Packet 3: Geometry

Key vocabulary over statistics and probability.
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Sum of Interior Angles
measure of an interior angle of a regular polygon
"the sum of all angles divided by the number of angles"
regular polygon
a polygon with equivalent sides and angles
formula for "Sum of interior angles"
(n - 2)180
sum of exterior angles
formula for the sum of exterior angles
always 360
measure of an exterior angle of a regular polygon
"the sum of all angles divided by the number of angles"
formula for an exterior angle of a regulary polygon
360/n
point of concurrency
where three lines meet/intersect
"regular" polygon
equal sides and equal angles
Centroid of a triangle
point of concurrency of the medians; always inside the triangle
median
cuts a line segment in half
Incenter of a triangle
point of concurrency of the angle bisectors; always inside the triangle
angle bisector
cuts an angle in half
Circumcenter of a triangle
point of concurrency of perpendicular bisector; can be inside or outside of the triangle
perpendicular bisector
A line that is perpendicular to a segment at its midpoint.
Orthocenter of a triangle
point of concurrency of the altitudes; can be inside or outside of the triangle
altitude
goes from the vertex to the opposite side, forming a 90 degree angle
vertical angles
a pair of opposite congruent angles formed by intersecting lines
complementary angles
Two angles whose sum is 90 degrees
supplementary angles
Two angles whose sum is 180 degrees
distance formula
d = √[( x₂ - x₁) + (y₂ - y₁)]
midpoint formula
M = [ (x₁ + x₂) / 2, (y₁ + y₂) / 2 ]
perpendicular lines
lines that form a 90 angle; their slopes are opposite reciprocals.
Ex: if the slope of a line is 1/2, the slope of the perpendicular line is -2.
parallel lines
lines that have the same slope, so they never intersect
perimeter
the some of all sides
area
the number of square units needed to cover a flat surface