Creating Regular Polygons: Ex. 1

DIRECTIONS:
In the GeoGebra applet below,[br][br]1) Select the REGULAR POLYGON [icon]/images/ggb/toolbar/mode_regularpolygon.png[/icon] tool. Then plot 2 points [i]A[/i] and [i]B[/i]. [br] In the pop-up box that appears, enter "3" (without the " "). [br] This creates an "regular triangle" (equilateral & equiangular triangle). [br][br]2) Now use this same tool to construct a regular quadrilateral (square) and regular octagon. [br][br]3) Select the MOVE [icon]/images/ggb/toolbar/mode_move.png[/icon] tool. Move any one (or more) of the [b][color=#1e84cc]blue points[/color][/b] around. [br] Note these polygons always remain regular. [br][color=#0000ff][br]When you're done (or if you're unsure of something), feel free to check by watching the quick silent screencast below the applet.[/color]
Quick (Silent) Demo

Constructing Angle Bisectors: Ex. 11

DIRECTIONS:
1) Use the ANGLE BISECTOR [icon]/images/ggb/toolbar/mode_angularbisector.png[/icon] tool to construct the 3 angle bisectors of the triangle. [br][br]2) Use the INTERSECT [icon]/images/ggb/toolbar/mode_intersect.png[/icon]tool to plot the point of concurrency (incenter) of these 3 angle bisectors. [br][br]3) Go to the algebra view (left side). [br] Hide the 3 angle bisectors of this triangle (you've just constructed in step 1). [br][br]4) Use the PERPENDICULAR LINE [icon]/images/ggb/toolbar/mode_orthogonal.png[/icon] tool to construct a line that passes through the incenter and is perpendicular to [math]\overline{DE}[/math]. [br][br][color=#0000ff]Further directions appear below the applet. [/color]
5) Use the PERPENDICULAR LINE tool to construct a line that passes through the incenter and is perpendicular to [math]\overline{EF}[/math]. [br][br]6) Use the PERPENDICULAR LINE tool to construct a line that passes through the incenter and is perpendicular to [math]\overline{DF}[/math]. [br] [br]7) Use the INTERSECT tool to plot the 3 points at which the lines (you constructed in steps 4 - 6) intersect the 3 sides of the triangle. [br][br]8) Go to the STEPS window. Hide the 3 lines you constructed in steps 4 - 6. [br][br]9) Construct a circle with centered at the incenter that passes through any 1 of the points you constructed in step 7.
10)
What do you notice? Why does this occur?
[color=#0000ff]When you're done (or if you're unsure of something), feel free to check by watching the quick silent screencast below the applet. [/color]
Quick (Silent) Demo

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