Khan Academy
Proportional Relationships
Spot when two quantities grow together at a steady rate.
Watch on YouTubeTwo quantities that grow together at one steady rate.
Read this first — it covers the idea in plain language with a worked example.
Two quantities are proportional when they always change by the same rate. If you earn $12 every hour, dollars and hours are proportional — the rate stays 12 no matter how many hours you work.
Set two equal ratios next to each other and cross-multiply to find the missing value.
Solve 3/5 = x/20
Tip
A double number line or a table can help you see the steady rate when you get stuck.
Watch the main video, then check the second take if you want another explanation.
Spot when two quantities grow together at a steady rate.
Watch on YouTubeTry a worksheet or work through some problems before the quiz.
A couple of questions to make sure this topic stuck. Retake as many times as you want.
Proportional Relationships
If 5 notebooks cost $7.50, how much do 8 notebooks cost?