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Geometry Regents Vocabulary
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Gravity
Terms in this set (40)
undefined terms
points, lines, and planes are undefined becasue they only are explained through examples and descriptions
bisector
divides a measurement in half
point of concurrency
the point of intersection of concurrent lines (must be two or more)
incenter
the point of concurrency of the angle bisectors in a triangle
circumcenter
the point of concurrency of the perpindicular bisectors in a triangle
supplementary angles
the sum of two or more angles that equal 180 degrees
linear pair
angles that are supplementary and adjacent
vertical angles
two angles opposite each other when they intersect (vertical angles are always congruent)
angles at a point
angles at a point sum to 360 degrees
alternate interior angles
the pairs of angles on opposite sides of the transversal, but inside the two lines (when lines parallel/alt. int. angles are congruent)
correspoinding angles
the pairs of angles that are in matching corners (same location at each intersection)
auxillary line
a line drawn into a diagram to help solve the problem
exterior angle
an angle on the outside of a triangle
interior angle
an angle on the inside of a triangle
skew lines
lines that do not intersect and are not coplanar
rigid motion
a motion that preserves lines, rays, segments, and angle measures (rotation, reflection, translation)
line of symetry
a line that the image of the figure when reflected over it, is reflected onto its own image
rotational symetry
the rotation of a plane that maps an image onto itself
0 < X < 360
identity symetry
a transformation that maps each point in the plane back to the same point
similarity
have correspondences between triangles but the triangles are not congruent.
mid-segment
a line segment that joins the midpoints of two sides
median
line segment connecting the vertex of a triangle to the midpoint of the opposite side
centroid
point of intersection of the 3 medians in a triangle
scale drawings
use dilations
dilations
do not preserve distance, do preserve angle measure
conjecture
an educated guess based on known information
scale factor
the product of the scale factors of the dilations in the composition, if there is no dilation the scale factor is one
right triangle ratio
3, 4, 5
30-60-90 triangle ratio
1, 2, root of 3
45-45-90 triangle ratio
1, 1, root of 2
sine
opp/hyp
cosine
adj/hyp
tangent
opp/adj
complementary angles
two angles that add to 90 degrees
angle of elevation
the angle between the horizontal and the line of sight to see and object that is above the observer
angle of depression
the angle between the horizontal and the line of sight to see an object that is below the observer
positive slope
tangent of the angle of elevation of the line
negative slope
negative tangent of the angle of depression of the line
pythagorean identity
(sinX)^2+(cosX)^2=1
tanX=sinX/cosX
tangent is equal to the ratio of the sinX : cosX
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