7th Grade · Geometry
Proportional
7.G.A.1
Definition
Two figures are proportional if all pairs of corresponding sides have the same ratio (scale factor). Proportional figures have the same shape but different sizes.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
Examples
- Sides 6/3, 8/4 both equal 2 — proportional, scale factor 2.
- Sides 3,4,5 vs 6,7,10 give ratios 2, 1.75, 2 — not equal, NOT proportional.
Key rule
All corresponding sides must be in the same ratio AND corresponding angles equal.
Memory hook
Same shape, same ratio, different size.