Reflection About a Plane

In the applet below, the [b][color=#bf9000]yellow triangular pyramid[/color][/b] (with [b][color=#ff00ff]LARGE PINK VERTICES[/color][/b]) has been reflected about the [b][color=#999999]gray plane[/color][/b]. [br][br]You can alter the appearance of the [b][color=#bf9000]yellow pyramid (pre-image)[/color][/b] at any time by moving any one (or more) of the [b][color=#ff00ff]LARGE PINK VERTICES[/color][/b]. [br][br]You can change the orientation of the [b][color=#999999]plane[/color][/b] by moving any one (or more) of the [b][color=#ff7700]3 ORANGE POINTS[/color][/b] it passes through. [br][br][b]Explore! [/b][br][br]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?
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