22 terms

# Geometry Ch. 9 - Transformations

Vocab and other stuff from Ch. 9
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isometry
a transformation in which the preimage and image are congruent
reflection
a transformation representing a flip of the figure over a point, line, or plane
(a, -b)
the image of (a, b) reflected over the x-axis
(-a, b)
the image of (a, b) reflected over the y-axis
(-a, -b)
the image of (a, b) reflected through the origin
(b, a)
the image of (a, b) reflected over the line y = x
translation
a transformation that moves all points of a figure the same distance in the same direction
composition
a transformation made up of successive transformations
rotation
a transformation that turns every point of a preimage through a specified angle and direction about a fixed point
angle of rotation
the angle through which a preimage is rotated to form the image
rotational symmetry
If a figure can be rotated less that 360° about a point so that the image and the preimage are indistinguishable, then the figure has ___
order
# of rotations less than 360° that produce an image indistinguishable from the original
magnitude
360° divided by the order
tessellation
a pattern that covers a plane by transforming the same figure or set of figures so that there are no overlapping or empty spaces
regular
if a tessellation is formed by only one type of regular polygon, then the tessellation is ___
semi-regular
if a uniform tessellation is formed by more than one type of regular polygon, then the tessellation is ___
uniform
a tessellation that has the same arrangement of shapes and angles at each vertex is called ___
dilation
a transformation that enlarges or reduces a figure
enlargement
if |r| > 1, the dilation is a(n) ___
reduction
if 0 > |r| > 1, the dilation is a(n) ___
congruence transformation
if |r| = 1, the dilation is a(n) ___
(rx, ry)
if (x, y) is the preimage of a dilation centered at the origin with scale factor r, then the image is ___