Dilating Lines and Angles Practice (GeoGebra)

This example demonstrates how to perform a dilation (enlargement/shrinking) in the plane and how it transforms geometric objects such as lines and angles, highlighting the correspondence between pre-image and image. Key concepts include similarity and scale factor, the dilation mapping from points to points, and the way lines and angles behave under a transformation (e.g., preserved angle structure up to the dilation while directions and relative opening are reflected). For construction, although no explicit GeoGebra command list is provided in the construction summary, the work is centered on using GeoGebra’s transformation tools to generate the dilated versions of line/segment objects and angle objects; typically this involves applying a dilation/scale transform to the defining points, then constructing the image lines/segments and measuring or reconstructing the resulting angles (often using angle-definition and intersection/extension steps to identify the correct angle vertex and sides). Suitable for middle-school geometry and classroom practice on similarity and geometric transformations, as well as for interactive learning and enrichment.