1. Section 7.2 Reflections OBJECTIVE:
To find reflection images of figures
BIG IDEAS: Transformations and Coordinate Geometry
ESSENTIAL UNDERSTANDING:
When you reflect a figure across a line, each point of the figure goes to another point the same distance from the line, but on the other side.
MATHEMATICAL PRACTICE:
Make sense of problems and persevere in solving them

2. Reflection across a Line
A Reflection ( ) across a line m, called the line of reflection, is a transformation with the following properties:
If a point A is on line m, then the image of A is itself
(that is )
If a point B is not on line m, then m is the perpendicular bisector of
When you reflect a figure
the shapes have opposite
orientations but are equidistant
from the line.

3. Properties of Reflections
Reflections preserve ____________________
Reflections preserve _______________ measure
Reflections ____________ each point of the _______________ to one and only one corresponding point of its _______________
Reflections are _______________motions and _______________

4. EX 1: Find the coordinates of the imageb) c) d) e) f)

5. Reflection Rules
Reflections in the coordinate axes have the following properties:
If is reflected in the x-axis, its image is the point
If is reflected in the y-axis, its image is the point
If is reflected in the line , its image is the point the same units above or below or left or right of the line, respectively
If is reflected in the line , image is the point

6. EX 2: Find the coordinates of the image of the triangle
a) Graph points Graph the coordinates of

7. EX 2: Find the coordinates of the image of the triangle
b) Graph points Graph the coordinates of

8. 2 ribbons on L4 and Mastery on L5
Math IXL L4 and L5
2 ribbons on L4 and Mastery on L5