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>Triangles>How to Find Incircle and Incenter Using GeoGebra

How to Find Incircle and Incenter Using GeoGebra

You can use GeoGebra to find the incircle and incenter of a triangle.

GeoGebra Instruction 1

1.: Open Algebra View and Graphics View under View in Menu.
2.: Make a triangle with the vertices $A$ , $B$ , and $C$ by using the tool Polygon . Then, you need to click on three points in Graphics View where you want the vertices of the triangle to be. Finally, complete the triangle by clicking on the point that you started with.
3.: Click Angle Bisector by first clicking tool number 4, then tool number 4 in the drop-down list.
4.: Construct the angle bisector of $∠ A$ by clicking on $∠ B$ , $∠ A$ , and $∠ C$ in that order. To construct the angle bisector of $∠ B$ , click on $∠ A$ , $∠ B$ , and $∠ C$ in that order. Finally, click on $∠ B$ , $∠ C$ , and $∠ A$ to construct the angle bisector of $∠ C$ .
5.: Click Intersect by first clicking tool number 4, then tool number 4 in the drop-down list, and use it to find the point of intersection $D$ between two angle bisectors. The point $D$ is the incenter.
6.: Click Circle with Center through Point , and construct a circle using the incenter as the center. Expand it so that the circle touches one side of the triangle. You can then see that the circle actually touches all sides of the triangle. You’ve found the incircle!

Screenshot of GeoGebra showing a triangle with its incenter and incircle

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