Similar & Congruent Figures
Section: GeometryBank code: GEO-SCFGRE frequency: Medium-HighPro
1. Core Idea
- Congruent = same shape and same size. Corresponding sides and angles are all equal.
- Similar = same shape, possibly different size. Corresponding angles are equal, and corresponding sides are in a constant ratio.
The GRE tests similarity far more than congruence, and almost always through the scale factor:
| If lengths scale by k | then |
|---|---|
| areas scale by | k^2 |
| volumes scale by | k^3 |
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