Create a cube and intersect it with a plane to observe the intersection polygons.

[table][tr][td][size=100]1.[/size][/td][td][img]https://wiki.geogebra.org/uploads/thumb/4/40/Menu_view_algebra.svg/32px-Menu_view_algebra.svg.png[/img][/td][td][size=100]Enter [code]a x + b y + c z = d[/code][code] [/code]into the[i] Input[/i][i] Bar[/i] to create a plane.[br][/size][/td][/tr][tr][td][size=100]2.[/size][/td][td][size=100][/size][/td][td][size=100]After pressing [i]Enter [/i]sliders for values [i]a[/i], [i]b[/i], [i]c[/i] and [i]d [/i] will be created automatically.[/size][/td][/tr][tr][td][size=100]3.[/size][/td][td][size=100][icon]/images/ggb/toolbar/mode_cube.png[/icon][/size][/td][td][size=100]Select the [i]Cube[/i] tool from the [i]3D Graphics View Toolbar[/i] and click on points [i](0, 0, 0)[/i] and [i](2, 0, 0)[/i] in the [i]3D Graphics View[/i].[/size][/td][/tr][tr][td][size=100]4.[/size][/td][td][size=100][icon]https://www.geogebra.org/images/ggb/toolbar/mode_intersectioncurve.png[/icon][/size][/td][td][size=100]Select the [i]Intersect Two Surfaces[/i] tool and click directly on one intersection segment to display the whole intersection polygon of the plane and the cube.[/size][/td][/tr][tr][td][size=100]5.[/size][/td][td][size=100][icon]/images/ggb/toolbar/mode_move.png[/icon][/size][/td][td][size=100]Select the [i]Move[/i] tool and change the slider values by dragging the point on the line.[/size][/td][/tr][tr][td][size=100]6.[/size][/td][td][size=100][icon]https://www.geogebra.org/images/ggb/toolbar/mode_rotateview.png[/icon][/size][/td][td][size=100]Hide the axes and the xOy-plane through the [img]https://wiki.geogebra.org/uploads/thumb/c/c5/Stylingbar_icon_graphics3D.svg/16px-Stylingbar_icon_graphics3D.svg.png[/img] [i]Style Bar[/i]. Select the [i]Rotate 3D Graphics View[/i] tool and drag the [img]https://wiki.geogebra.org/uploads/thumb/b/bb/Perspectives_algebra_3Dgraphics.svg/16px-Perspectives_algebra_3Dgraphics.svg.png[/img] [i]3D Graphics View[/i] to rotate the cube and the plane. [/size][/td][/tr][/table]