Mathematics for Teaching GeoGebra Activities What are the coordinates of points under reflection?

## What are the coordinates of points under reflection?

In Activity 1 you learned about the meaning of the coordinates of points on an x-y coordinate system, also called Cartesian coordinate system.

In this activity, you will learn how the points in the Cartesian plane are related. By the end of this activity you should be able predict the location of points in the quadrants as well as the coordinates of points which are reflections of each other along the x-axis and the y-axis. You will also learn in this activity how to use the “Reflect” tool of GeoGebra.

Activity 2
1. If you put a mirror along the y-axis, locate the reflections of the points A, B, C, D, E, F on the right side of the y-axis. Use the point tool [.A] to plot the points.

2. What do you notice about the coordinates of the set of points A, B, C, D, and E? How do their coordinates compare with the coordinates of their reflections?