8th Grade · Geometry
Preimage
8.G.A.1
Definition
The original figure before a transformation is applied. Its vertices are labeled with plain letters, while the transformed image uses primed letters.
Examples
- ABC is the preimage; A'B'C' is the image.
- Pre- means 'before' — the preimage comes first.
Key rule
The preimage is the input figure — the original, before any transformation.
Memory hook
The original, before anything happens to it.