Calculator Form
Choose a proportion problem type, enter the known values, then press calculate to see the solved result above this form.
Formula Used
1. Missing fourth term:
x = (b × c) ÷ a
2. Direct proportion:
y = kx, where k = y₁ ÷ x₁
3. Inverse proportion:
xy = k, so y₂ = (x₁ × y₁) ÷ x₂
4. Percentage proportion:
Part = Whole × Percent ÷ 100
5. Ratio sharing:
Share = (ratio part ÷ total ratio) × total amount
6. Recipe scaling:
Scaled quantity = Base quantity × (Target servings ÷ Base servings)
7. Map scale:
Actual distance = Map distance × scale denominator
8. Unit rate projection:
Projected cost = (Cost ÷ Quantity) × Target quantity
These formulas cover common classroom and real-world proportion word problems involving ratios, rates, scaling, percentages, distances, and shared totals.
How to Use This Calculator
- Select the problem type that matches your word problem.
- Enter the known values in the visible input boxes.
- Add labels and units to make results easier to read.
- Choose the number of decimal places you want.
- Press Calculate Proportion to solve the problem.
- Review the answer, formula, worked steps, and graph.
- Use the CSV or PDF buttons to export the result.
- Reset the form to solve a new problem quickly.
Example Data Table
| Problem Type | Given Data | Question | Answer |
|---|---|---|---|
| Missing Fourth | 3 : 12 = 5 : x | Find x | 20 |
| Direct Proportion | 4 books cost 28 | Cost of 9 books | 63 |
| Inverse Proportion | 6 workers need 10 days | Days for 15 workers | 4 |
| Percentage Proportion | 18% of 250 | Find the part | 45 |
| Ratio Sharing | 540 shared in 2 : 3 : 4 | Find each share | 120, 180, 240 |
| Recipe Scaling | 350 g for 4 servings | Need for 10 servings | 875 g |
| Map Scale | 7.5 cm at 1 : 50,000 | Actual distance | 3.75 km |
| Unit Rate | 18 dollars for 6 items | Cost of 14 items | 42 |
FAQs
1. What types of word problems can this calculator solve?
It solves missing fourth terms, direct proportion, inverse proportion, percentages, ratio sharing, recipe scaling, map scale problems, and unit rate projections.
2. When should I use direct proportion mode?
Use direct proportion when both quantities increase together or decrease together at the same constant rate, such as price by quantity or distance by time.
3. When should I use inverse proportion mode?
Use inverse proportion when one quantity rises while the other falls so their product stays constant, such as workers and completion time.
4. Can this calculator help with classroom homework?
Yes. It shows formulas, worked steps, and a graph, making it useful for homework checks, revision, and guided classroom practice.
5. Why are labels and units included?
Labels and units make the output easier to read. They help connect the math result to the actual word problem context.
6. Does the graph change for each problem type?
Yes. The chart updates according to the selected mode. Some modes show bar comparisons, while ratio sharing and percentage mode use pies.
7. What happens if I leave a required field empty?
The calculator shows an error message above the form. Enter the missing values, then calculate again to see the result.
8. Can I export the results for reports or study notes?
Yes. After calculation, you can download the solved result as a CSV file or a PDF summary for printing or saving.