三角形的内切圆

Task
Construct the incircle of a triangle.[br][br]Explore the construction below and explore how to create the incircle of a triangle with [i][url=https://www.geogebra.org/calculator][i]GeoGebra Calculator Suite[/i][/url][/i]. Then try it yourself by following the instructions below.[br]
Explore the construction...
Instructions
[b]Note:[/b] If you're using the Mobile App make sure that the chosen [i]Labeling[/i] option is [i]New Points Only[/i]. You can change this by going to the [i]Settings [/i]in the app's menu and then selecting [i]General.[/i][br][br][table][tr][td]1.[/td][td][icon]https://www.geogebra.org/images/ggb/toolbar/mode_polygon.png[/icon][/td][td]Create a triangle [i]ABC[/i] using the [i]Polygon[/i] tool.[/td][/tr][tr][td]2.[/td][td][icon]https://www.geogebra.org/images/ggb/toolbar/mode_angularbisector.png[/icon][/td][td]Select the [i]Angle [/i][i]Bisector[/i] tool and create the angle bisector for two angles of the triangle.[br][b]Hint:[/b][b] [/b]Selecting the three points [i]A[/i], [i]B[/i], and [i]C[/i] produces the angle bisector of the enclosed angle.[/td][/tr][tr][td]3.[/td][td][icon]https://www.geogebra.org/images/ggb/toolbar/mode_intersect.png[/icon][/td][td]Create the intersection point [i]D[/i] of the two angle bisectors using the [i]Intersect[/i] tool.[/td][/tr][tr][td]4.[/td][td][icon]https://www.geogebra.org/images/ggb/toolbar/mode_orthogonal.png[/icon][/td][td]Select the [i]Perpendicular Line[/i] tool and create a perpendicular line to one side of the triangle, through point [i]D[/i].[/td][/tr][tr][td]5.[/td][td][icon]https://www.geogebra.org/images/ggb/toolbar/mode_intersect.png[/icon][/td][td]Create the intersection point [i]E[/i] of the perpendicular line and the chosen side of the triangle using the [i]Intersect[/i] tool.[/td][/tr][tr][td]6.[/td][td][icon]https://www.geogebra.org/images/ggb/toolbar/mode_circle2.png[/icon][/td][td]Select the [i]Circle with Center[/i] tool and construct the incircle with center [i]D[/i] through point [i]E[/i].[/td][/tr][tr][td]7.[/td][td][icon]https://www.geogebra.org/images/ggb/toolbar/mode_showhideobject.png[/icon][/td][td]Hide the auxiliary lines used for the construction.[/td][/tr][tr][td]8.[/td][td][icon]https://www.geogebra.org/images/ggb/toolbar/mode_segment.png[/icon][/td][td]Connect points [i]D[/i] and [i]E[/i] using the [i]Segment[/i] tool to display the radius of the incircle.[/td][/tr][tr][td]9.[/td][td][icon]https://www.geogebra.org/images/ggb/toolbar/mode_angle.png[/icon][/td][td]Show the right angle between the incircle's radius and the corresponding side of the triangle using the [i]Angle[/i] tool.[/td][/tr][tr][td]10.[/td][td][icon]https://www.geogebra.org/images/ggb/toolbar/mode_move.png[/icon][/td][td]Select the [i]Move[/i] tool and drag the vertices of the triangle to check if your construction is correct.[/td][/tr][/table]
Try it yourself...

Information: 三角形的内切圆