Institutional Ratio Suite
Cross-Multiplication & Aspect Scale
Proportion Calculator
Solve proportions and cross multiplication.
Proportion Solver (A / B = C / D)
Solve for any unknown variable in a proportion using cross-multiplication proofs.
Solve for unknown:
=
Calculated Solution
C = 12
Algebraic Derivation:
Equation: 3 / 5 = C / 20
Cross-multiply: C × 5 = 3 × 20
C = (3 × 20) ÷ 5 = 12
Complete Mathematical Handbook
The Complete Mathematical Guide to Ratios, Proportions & Dimensional Scaling
A ratio expresses the quantitative relationship between two numbers, indicating how many times the first value contains or is contained within the second value. When two ratios are equated to one another, they form a proportion ($A/B = C/D$). Proportions are the fundamental mechanism underlying scale drawings, currency exchange rates, mechanical gear ratios, concrete mixes, and screen aspect ratios in digital video production.
Ratio Simplification & Cross-Multiplication
Mathematical proofs for Euclidean GCD reductions, proportion cross-products, and part-to-whole sums.
Aspect Ratio Standards & Screen Scaling
Direct comparison of 16:9, 4:3, and 1:1 viewports alongside proportional financial partitioning.
Frequently Asked Ratio & Proportion Questions
About Proportion Calculator
Institutional ratio and proportion calculator suite with cross-multiplication solver, aspect ratio scaler, and financial partitioning.
Why this page helps
- Instantly resolves photography, digital design, and video aspect ratios
- Prevents errors in financial partnership equity distribution
- Step-by-step cross-multiplication algebra proofs
How to use it well
- Select your calculation mode: Ratio Simplifier, Proportion Solver, Amount Partitioner, or Aspect Ratio Rescaler.
- Enter known quantities into the labeled numeric fields.
- Review the simplified fraction, decimal equivalent, and proportion validation.
- Save results to history or export as PDF report.
Expert tips
- Remember that ratios scale multiplicatively; never add or subtract terms directly from a ratio.
- For screen scaling, maintain exact aspect ratios to avoid pixel distortion in responsive UI.