# Reflection About a Plane

- Author:
- Tim Brzezinski

- Topic:
- Reflection

In the applet below, the

**yellow triangular pyramid**(with**LARGE PINK VERTICES**) has been reflected about the**gray plane**. You can alter the appearance of the**yellow pyramid (pre-image)**at any time by moving any one (or more) of the**LARGE PINK VERTICES**. You can change the orientation of the**plane**by moving any one (or more) of the**3 ORANGE POINTS**it passes through.**Explore!**Be sure to answer the question that follows.## 1.

Suppose you stand 4 ft away from a mirror. How far would your image be away from the glass (assuming you could "reach in" and measure)? How is your conclusion somewhat supported by any dynamics you see here?