Activity Overview
Transformation are significantly more powerful when they are created and explored in a dynamic, digital environment. In this activity students perform a series of dilations on triangles and quadrilaterals in a geometry environment and also on the Cartesian plane. They explore variant (length and area) and invariant (angle) properties in a simple yet powerful visual experience.
Objectives
Students understand the term dilation through geometric objects which makes it much easier to transfer this knowledge and understanding to more abstract concepts like dilations performed on a function or graph. Terminology like ‘dilation from the x axis’ or ‘dilation from the y axis’ make much more sense, so too the dilation factor when students have a solid understanding formed around more concrete examples such as shapes.
Vocabulary
- Dilation
- Dilation from a point
- Dilation factor
- Vertex
- Length
- Area
- Angle
- Invariant
About the Lesson
Students create shapes in the Geometry application and then dilate them using the corresponding transformation tool. Students are able to experiment, measure lengths, area and angles to see which elements change (variant) or which stay the same (invariant) through the transformation process.