8th Grade · Geometry
Congruent
8.G.A.2
Definition
Having exactly the same size and shape. Two figures are congruent if a sequence of rigid motions maps one onto the other, making all corresponding parts equal.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
Examples
- If △ABC ≅ △DEF, then AB = DE, BC = EF, CA = FD.
- Congruent means same size AND same shape; similar means same shape, possibly different size.
Key rule
A rigid motion (slide, flip, turn) maps congruent figures exactly onto each other.
Memory hook
Same size, same shape, exactly.