Ontario · Grade 8
G8.B2.8
Grade 8 — Solve problems involving rates, ratios and proportions in various contexts.
Grade 8 — Compare proportional situations and determine unknown values in proportional situations, and apply proportional reasoning to solve problems in various contexts.
A note on this mapping: The same expectation is tagged on Ratios & Proportions; this skill is the graph-and-equation half of it — the constant of proportionality and y = kx.
The 2 skills that cover it
- Ratios & ProportionsCompare quantities with ratios, find unit rates, and solve proportions that scale a relationship up or down.Read the lesson →
- Proportional RelationshipsRecognise when two quantities grow in lockstep, find the constant of proportionality from a table, a graph or an equation, and compare unit rates across representations.Read the lesson →
What a student should be able to do
- Write and simplify a ratio, and find an equivalent ratio.
- Compute a unit rate and use it to compare deals.
- Solve a proportion for an unknown value.
- Use proportional reasoning for scaling, recipes and maps.
- Decide whether a table, a graph or an equation shows a proportional relationship.
- Find the constant of proportionality k and write the equation y = kx.
- Read the unit rate off a graph as the y-value at x = 1 and interpret the point (1, k).
- Compare two proportional relationships given in different forms.