# G.GCI.3 Constructing an Incenter: Ex. 11

- Author:
- Dan Dale, Tim Brzezinski

## DIRECTIONS:

1) Use the ANGLE BISECTOR tool to construct the 3 angle bisectors of the triangle.
2) Use the INTERSECT tool to plot the point of concurrency (incenter) of these 3 angle bisectors.
3) Go to the STEPS window.
Hide the 3 angle bisectors of this triangle (you've just constructed in step 1).
4) Use the PERPENDICULAR LINE tool to construct a line that passes through the incenter and is perpendicular to .
Further directions appear below the applet.

5) Use the PERPENDICULAR LINE tool to construct a line that passes through the incenter and is perpendicular to .
6) Use the PERPENDICULAR LINE tool to construct a line that passes through the incenter and is perpendicular to .
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.
8) Go to the STEPS window. Hide the 3 lines you constructed in steps 4 - 6.
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?

When you're done (or if you're unsure of something), feel free to check by watching the quick silent screencast below the applet.