Proportion and Proportional Division
Two ratios set equal, and a total split in a given ratio. Scaling both terms of a ratio leaves it unchanged, which is what lets an unknown be carried as a multiplier and pinned down by one extra condition -- a sum, a difference, or a product of extremes. Sharing a profit or a length in a ratio is the same idea run forwards.
grade 6–8 RatiosExpressions Convert to AlgebraLook for a Pattern
Progression (6)
g6 1. Scale a simple ratio up to bigger numbers Ratios
g7 2. Write the rate as a fraction to read off both terms Ratios
g6 3. Scaling both terms keeps the ratio RatiosExpressions
g7 4. Reduce the investment ratio to whole numbers Ratios
g7 5. Write the daily gain or loss as a proportion Ratios
g7 6. Equal heights make the area ratio the base ratio GeometryRatios