Grade 6 · Spatial Sense · Geometry and Transformations
Transform Shapes on the Plane
Coordinates precisely describe location. Transformation rules predict how every point of a shape moves.
The big idea
Apply the same transformation to every vertex
Reflecting across the y-axis changes (x, y) to (−x, y). A 90° counter-clockwise rotation about the origin changes it to (−y, x).
Work it through
Transform the point (4, −2)
- 1. Reflect across the y-axis: (4, −2) becomes (−4, −2).
- 2. Rotate the reflected point 90° counter-clockwise.
- 3. Use (x, y) → (−y, x): (−4, −2) becomes (2, −4).
- 4. Check that distance from the origin is preserved.