Reflections

Chapter 3 Section 7

Reflections

A reflection – is a transformation that flips an image over a line. o This line is called the

line of reflection.o Written Rline(P) = P

Ry-axis(C) = C’

Example

P(-1, 2)

1. Rx-axis(P) =? 2. Ry-axis(P)= ? 3. Ry=1(P)=?

Example

A(3, -2)

1. Rx-axis(A) =? 2. Ry-axis(A)= ? 3. Ry=1(A)=?

Example

ABC has vertices A(1, 1), B(1, 6) and C(4, 1).

Ry-axis(ABC)

Example

LMN has vertices L(0, 0), M(3, -5) and N(-2, -2).

Rx-axis(LMN)

Example

ABC has vertices A(0, 2), B(3, 0) and C(6, 3).

1. Rx-axis(ABC)

2. Ry-axis(ABC)

Find the coordinates of the image for each reflection:

1. Rx-axis(A)

2. Ry-axis(B)

3. Ry-axis(F)

4. Rx-axis(E)

Draw the Image for Each Reflection

ABC has vertices A(2, 0), B(2, 5) and C(6, 5).

1. Rx-axis(ABC)

2. Ry-axis(ABC)

Reflectional Symmetry

A figure has reflectional symmetry if it can be reflected over a line so that the image and pre-image match up

o The line that divides a figure up into mirror images is called the line of reflection.

Example:

How many lines of symmetry does each letter

have? 1. E

2. B

3. X4. P

Do the flags have reflectional symmetry?

1. 2.

3.