do now describe the translations in words. 1. 1. (x, y) (x – 5, y + 3) 2. 2. (x, y) (x + 2, y...

Do NowDo Now

Describe the translations in words.

1. (x, y)(x – 5, y + 3)

2. (x, y)(x + 2, y - 1)

3. (x, y)(x + 0, y + 2)

Do Now cont’dPlot the points, then find the coordinates of the

image after the

given

translation.

4. A(2, -2)

B(4, 2)

C(7, -1)

(x, y)(x – 6, y + 4)

Do Now cont’dPlot the points, then find the coordinates of the

image after the

given

translation.

5. D(-4, 1)

E(-1, 2)

F(-1, 0)

G(-3, -1)

(x, y)(x + 2, y + 3)

Section 12.5Section 12.5Perform ReflectionsPerform Reflections

Objective: use reflections and symmetryObjective: use reflections and symmetry

Homework:Homework:

12.5 Worksheet12.5 Worksheet

VocabularyVocabulary

ReflectionReflection: transformation that uses a line : transformation that uses a line like a mirror to reflect an imagelike a mirror to reflect an image

(flip an image over a line) (flip an image over a line)

Line of reflectionLine of reflection: the line that acts as a : the line that acts as a mirrormirror

Identify ReflectionsIdentify Reflections

Reflection in the x axisReflection in the x axis

Triangle DEF is the image of triangle ABC after a reflection in the x axis.

Point A is 2 spaces away from the x axis, so

Point D is 2 spaces away from the axis.

A(-7, 2) B(-3, 2) C(-3, 4)

D(-7, -2) E(-3, -2) F(-3, -4)

Rule for reflection in the x axis: (x, y) → (x, -y)(x, y) → (x, -y)

Reflection in the x axisReflection in the x axisGraph triangle Graph triangle

ABC with ABC with vertices vertices A(4, 2) B(5, A(4, 2) B(5, 6) C(7, 3)6) C(7, 3)

Graph the image Graph the image of triangle of triangle ABC after a ABC after a reflection in reflection in the x-axis the x-axis and list the and list the coordinates coordinates of the of the image.image.

Reflection in the y axisReflection in the y axisGraph segment Graph segment

GE with GE with verticesvertices

G(-3, 4) E(2, -1)G(-3, 4) E(2, -1)

Graph the image Graph the image of segment GE of segment GE after a after a reflection in reflection in the y-axis and the y-axis and list the list the coordinates of coordinates of the image.the image.

Rule for reflectionRule for reflectionin the y axis: in the y axis: (x, y) → (-x, y)(x, y) → (-x, y)

ExamplesExamples

Line SymmetryLine Symmetry

Line of symmetry - line that divides a figure Line of symmetry - line that divides a figure into two equal partsinto two equal parts

Example: How manyExample: How manylines can you drawlines can you drawthrough the heart tothrough the heart toget equal parts?get equal parts?

Line symmetryLine symmetry

Determine the number of lines of Determine the number of lines of symmetry for the figuresymmetry for the figure