Do the ratios form a proportion: word problems
Key notes:
A proportion is a statement that two ratios are equivalent to each other. Two ratios form a proportion if their cross products are equal.
Learn with an example
✏️ Do these ratios form a proportion?
8 large paper clips to 12 small paper clips
12 large paper clips to 18 small paper clips
- yes
- no
Write the ratios as fractions.
8/12 and 12/18
Compare the two fractions to see if they are equivalent.
8/12 = 12/18
8 × 18 = 12 × 12 Multiply both sides by 12 × 18
144 = 144 Simplify
The cross products are equal, so the ratios form a proportion.
✏️ Do these ratios form a proportion?
9 large rugs to 18 small rugs
1 large rug to 2 small rugs
- yes
- no
Write the ratios as fractions.
9/18 and 1/2
Compare the two fractions to see if they are equivalent.
9/18 = 1/2
9 × 2 = 18 × 1 Multiply both sides by 18 × 2
18 = 18 Simplify
The cross products are equal, so the ratios form a proportion.
✏️ Do these ratios form a proportion?
16 biscuits to 10 brownies
8 biscuits to 5 brownies
- yes
- no
Write the ratios as fractions.
16/10 and 8/5
Compare the two fractions to see if they are equivalent.
16/10 = 8/5
16 × 5 = 10 × 8 Multiply both sides by 10 × 5
80 = 80 Simplify
The cross products are equal, so the ratios form a proportion.
let’s practice! 🖊️
