In this lesson you will demonstrate an understanding
of and apply simple geometric transformations using
combinations of slides, flips, and turns.
Vocabulary:
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acute
angle
cube
diagonal
equilateral
hexagon
isosceles
obtuse
octagon
parallelogram
pentagon
perpendicular
quadrilateral
rhombus
right angle
trapezoid
vertex (vertices)
reflection (flip)
rotation (turn)
translation (slide)
transformation
Tips to Remember:
Transformation
When you move a figure, you are actually creating a
new figure. The new figure is called an image while the
original figure is called its preimage. If each point
of the original figure is paired exactly with one point
of the image, and if each point of the image is paired
with exactly one point of the preimage, then this is
called a transformation.
Reflection (Flipping)
A reflection image is a new figure obtained
by flipping a figure along a line of reflection. Here
is an example of a figure being reflected or flipped.
Translation (Sliding)
The new figure when the figure is slid without
flipping or turning it. When sliding a figure you will
be told the direction and how far to slide it usually
stated in number of units. Here is an example of a figure
sliding.
Rotation (Turning)
When you slide and turn a figure upon a given
point, the new figure is called a rotation image. When
rotating a figure, there will be a point about which
the figure rotates or turns on. The center point of
rotation is usually a point on the figure (vertex),
but may also be a point within the figure as well. Here
is an example of a figure that has been rotated about
point A.
Congruent Polygons
Two polygons or figures are congruent if their
sides and angles can be placed in a correspondence such
that corresponding sides are congruent and corresponding
angles are congruent. In other words, if you can slide,
flip, or turn one of the figures to fit exactly on the
other the two figures are congruent. We use the symbol,
to
show two figures being congruent.
to
show two figures being congruent.