# Reflecting about Y = X and Y = -X (Ver 1)

- Author:
- Tim Brzezinski

- Topic:
- Coordinates, Geometry, Straight Lines, Reflection

## Here, we are REFLECTING Lisa's pic ABOUT A LINE. Now reposition the line so it coincides (lies on top of) the line Y = X.

## In the app above, move Lisa around to get different primage points. Then, record their images in the image column.

Take a look at the table of data above. Suppose a point **( a, b) is reflected about the line y = x**. What would the coordinates of its image be? Express in terms of

**and**

*a*

*b*.## Now reposition the line so it coincides (lies on top of) the line Y = -X.

## In the app above, move Lisa around to get different primage points. Then, record their images in the image column.

Take a look at the table of data above. Suppose a point **( a, b) is reflected about the line y = -x. **What would the coordinates of its image be? Express in terms of

**and**

*a*

*b*.