Construct a square by following the construction steps below.
[size=100][table][tr id=kstep_1][td]1.[/td][td][icon]/images/ggb/toolbar/mode_segment.png[/icon][/td][td]Select the [i]Segment [/i]tool. Click twice in the [i]Graphics View[/i] in order to create two points [i]A[/i] and [i]B[/i], and a segment between them.[br][/td][/tr][tr id=kstep_2][td]2.[/td][td][icon]https://tube.geogebra.org/images/ggb/toolbar/mode_orthogonal.png[/icon][/td][td]Activate the [i]Perpendicular Line[/i] tool. Create a line [i]g[/i] that is perpendicular to segment [i]AB[/i] and runs through point [i]B.[/i][br][/td][/tr][tr id=kstep_3][td]3.[br][/td][td][icon]/images/ggb/toolbar/mode_circle2.png[/icon][/td][td]Select the [i]Circle with Center through Point[/i] tool and construct a circle [i]c[/i] with center [i]B[/i] through point [i]A[/i].[br][/td][/tr][tr id=k_step44][td]4.[/td][td][icon]https://tube.geogebra.org/images/ggb/toolbar/mode_intersect.png[/icon][/td][td]Select the [i]Intersect[/i] tool. Intersect the perpendicular line [i]g[/i] with the circle [i]c[/i] to get the intersection point [i]C[/i].[br][/td][/tr][/table][/size]
[size=100][table][tr id=kstep_5][td]5.[/td][td][icon]https://tube.geogebra.org/images/ggb/toolbar/mode_orthogonal.png[/icon][/td][td]Construct a perpendicular line [i]h[/i] to line [i]AB[/i] that runs through point [i]A[/i].[/td][/tr][tr id=step_6][td]6.[/td][td][icon]https://tube.geogebra.org/images/ggb/toolbar/mode_orthogonal.png[/icon][/td][td]Construct another perpendicular line[i] i[/i] to line [i]g[/i] through point C.[/td][/tr][tr id=k_step77][td]7.[/td][td][icon]https://tube.geogebra.org/images/ggb/toolbar/mode_intersect.png[/icon][/td][td]Create the intersection point D of the line [i]h[/i] and line [i]i[/i].[br][/td][/tr][tr id=kstep_88][td]8.[/td][td][icon]https://tube.geogebra.org/images/ggb/toolbar/mode_polygon.png[/icon][/td][td]Select the [i]Polygon [/i]tool. Create the square [i]ABCD[/i] by respectively selecting all four vertices[i].[/i][br][/td][/tr][tr id=moveSquare][td]9.[/td][td][icon]/images/ggb/toolbar/mode_move.png[/icon][br][/td][td]Use the [i]Move[/i] tool in order to drag the vertices of the square and observe, how the construction adapts to your modifications.[/td][/tr][/table][/size]
Which construction step of the instructions above is responsible for the equal side lengths of the constructed square?