Translation is when we slide a figure in any direction.
Reflection is when we flip a figure over a line.
Rotation is when we rotate a figure a certain degree around a point.
Dilation is when we enlarge or reduce a figure.
for a reflection in the x-axis
1
0
0 -1
for a reflection in the y-axis
-1 0
0
1
for a reflection in the origin
-1 0
0
-1
for a reflection in the line y=x
0 1
1 0
Rotation 90 counter clockwise
0 -1
1 0
Counter clockwisw 180
-1 0
0 -1
Clockwise 90 or countercloskwise 270
0 1
-1 0
Reflection
A shape can be reflected across a line of reflection to create an image.
The line of reflection is also called the mirror line.
The triangle PQR has been reflected in the mirror line to create the image P'Q'R'.
Reflection is Error! Filename not specified.an example of a transformation. A transformation
is a way of changing the size or position of a shape.
Every point in the image is the same distance from the mirror line as the original shape.
The line joining a point on the original shape to the same point on the image is perpendicular
to the mirror line.
For example, the line between R and R' is perpendicular to the mirror line.
The equation of the line of symmetry
To describe a reflection on a grid, the equation of the mirror line is needed.
Example
Reflect the shape in the line
The line
.
is a vertical line which passes through -1 on the -axis.
Question
Describe the transformation of the shape ABC.