Four Types of Transformations

1
Four Types of Transformations

• Translation (Slide)

• Reflection (flip)

2
Four Types of Transformations

• Dilation (shrinking/stretching)

• Rotation (turn)

3
Reflections
4
Reflections/Flips

• When you reflect a shape in the coordinate plane,
  you reflect it over a line. This line is called
  the line of reflection.
•  When a figure is reflected on a coordinate
  plane, every point of the figure must have a
  corresponding point on the image..
•  Most reflections are over the x axis , the y -
  axis or another line.

5
Reflections

• When you reflect a shape over the x-axis, the
  x-coordinate stays the same and the y-coordinate
  changes to its oppoisite.
• (x, y)?(x, -y)
• When you reflect a shape over the y-axis, the
  x-coordinate changes to its opposite and the y
  stays the same.
• (x, y) ?(-x, y)

6

• EX. 1. Reflect the triangle over the x-axis and y
  axis. Draw the preimage and the images in
  different colors. Write the coordinates of the
  images. ?ABC has vertices
• A (-2, -2),
• B (-5, -4),
• C(-1, -5).

C
B
A
5
4
2
2
A
A
2
2
4
5
B
5
B
5
1
1
C
C
7
Reflections

• You can use the two rules to reflect a figure
  across line r.
• If a point A is on line r, then the image of A is
  A itself (that is, A A).
• If a point B is not on line r, then r is the
  perpendicular bisector of BB.

8
Reflections

• A point on the line of reflection is mapped onto
  itself.
• A point and its image are equidistant from the
  line of reflection.

9
Drawing Reflection Images

• Across X-axis

• Across the Y-axis