# G.GCO.2 and G.GCO.4 Exploring Line Reflections

- Author:
- Dan Dale, Tim Brzezinski

- Topic:
- Algebra, Geometry, Reflection

## DIRECTIONS:

*and*

**A***) anywhere you'd like within the coordinate plane. 2) Select the REFLECT ABOUT LINE tool. Then drag a rectangle around points*

**B***,*

**A***, and Wily's picture. This should cause these 3 items to become highlighted. Select the dashed line. 3) The images of these items should now appear. Please answer the questions that appear below the applet.*

**B**## 1.

Move the **ORANGE POINTS** so that the **dashed line lies right on top of the yAxis. **
What do you have as Wily's corner points ( ?, ??). Write them down below.
What are the coordinates of the images of these points? Please record these below too.
Do you notice anything interesting? Explain.

## 2.

According to your observations from (1), **what would the image of any point (x, y) after being reflected about the yAxis?** (Write your response in terms of x and y).

## 3.

Move the **ORANGE POINTS** so that the** dashed line lies right on top of the xAxis. **
What do you have as Wily's corner points ( ?, ??). Write them down below.
What are the coordinates of the images of these points? Please record these below too.
Do you notice anything interesting? Explain.

## 4.

According to your observations from (1), **what would the image of any point (x, y) after being reflected about the xAxis? ** (Write your response in terms of x and y).

## 5.

Move the **orange points **so the equation of the line becomes .
**What is the image of point ( a, b) under a reflection about the line **

**?**

## 6.

Move the 2 **orange points** around to change the equation of the line to .
**What is the image of point ( a, b) under a reflection about the line **

**?**