Idea 11of 22Builds onAdding the same to both breaks a ratio
Are two ratios equivalent?
How can you tell if two ratios are equivalent?
Today you'll discover
- how to find the scale factor
- why both terms must pass
- how a ratio table settles it
Think firstIs 10 : 15 the same ratio as 2 : 3?
Is 10 : 15 equivalent to 2 : 3?
Decide first, then press Next. Check the top term and the bottom term.
A ratio table, orange on top and blue below: 2 and 3 in the first column, 10 and 15 in the second. Curved arrows marked times 5 join them over the top and under the bottom; then the second column is ringed and 2 : 3 = 10 : 15 is written under it. The last step shows 2 and 3, 4 and 6, 6 and 9.
See the whole ideathe big idea and the key word, in one place
The big idea
Two ratios are equivalent when both terms share the same scale factor.
Two tests10 : 15: 2 × 5 = 10 and 3 × 5 = 15, equivalent. 10 : 14: 2 × 5 = 10, but 3 × 5 is 15, not 14.
Same tableTwo ratios that sit in the same ratio table are equivalent to each other.
Key word
- scale factor
- the number both terms of a ratio are multiplied or divided by to make an equivalent ratio
Ready to use it?
- Decide whether two ratios are equivalent.
- Find the scale factor between two ratios.