Ratio Tables

A ratio table lists a series of equivalent ratios side by side, each one scaled up (or down) from the original by the same multiplier. It turns the abstract idea of “equivalent ratios” into a simple, visual tool: once you spot the pattern across the columns, filling in a missing value becomes a matter of multiplying or dividing consistently.

Building a Ratio Table

Start with a base ratio, then multiply both numbers by the same amount to generate each new column – the ratio between the two rows always stays equivalent.

Build a ratio table for 2:5, showing the next 3 columns.

Multiplying both numbers by 2, 3, and 4: 2:5, 4:10, 6:15, 8:20.

Finding the Scale Factor

A ratio table shows 3:7 scaling to 15:?. What is the scale factor, and what is the missing number?

Scale factor: 15 ÷ 3 = 5. Missing number: 7 × 5 = 35.

Real-Life Application

Recipe planning: scaling ingredients for different numbers of servings.
Currency conversion: a table of equivalent amounts in two currencies.
Fuel efficiency: a table showing distance travelled for different amounts of fuel.

Key Takeaways

A ratio table lists equivalent ratios, each scaled by the same multiplier.
Finding the scale factor between two known values lets you fill in any missing value.
Ratio tables make scaling ratios visual and mistake-resistant.

Practice: Ratio Tables

Fill in the Ratio Table