How to Use:

1. Top Row: Enter the known relationship. (e.g., “10 shirts” $\to$ “$150$ production cost”).
2. Bottom Row (Left): Enter the new quantity you want to calculate for. (e.g., “25 shirts”).
3. Result: The tool calculates the proportional value ($x$) instantly.

FAQ:

• What is “Direct” vs “Inverse” proportion? This tool calculates Direct Proportion (as one goes up, the other goes up).
• Can I use decimals? Yes, it supports full decimal precision for weights (kg/grams) and currency.
• Why is Value A important? Value A cannot be zero, as you cannot divide by zero in mathematics.

Practical Fashion Use

• Fabric Sourcing: If $5$ yards of lace costs $\$120$, you can find out exactly how much $13$ yards will cost before placing a purchase order.
• Pattern Grading: If a size “Small” sleeve is $60$cm long for a $100$cm tall person, you can use the Rule of Three to estimate the sleeve length needed for a $120$cm tall child.
• Dye Formulation: If $10$ grams of pigment is required for $1$ liter of water, use this tool to find exactly how much pigment is needed for a specific vat size ($4.5$ liters).
• International Pricing: If your local price is $80$ Euros for a product that sells for $95$ Dollars, you can use the ratio to find the equivalent price for a $150$ Dollar item.