Understanding Three-Part Ratios
A three-part ratio compares three quantities simultaneously. Written as A:B:C, it shows the relative sizes of three values. Simplifying a three-part ratio involves dividing all three numbers by their greatest common divisor (GCD).
How to Simplify a Three-Part Ratio
- Find the GCD of all three numbers: GCD(A, B, C) = GCD(GCD(A, B), C)
- Divide each number by the GCD
- The result is the simplified ratio in lowest terms
Proportions from Ratios
Finding Proportions
Each part's proportion is its share of the total.
Proportion of A = A / (A + B + C)
Percentage Split
Convert each proportion to a percentage.
% of A = (A / Total) x 100
Decimal Ratios
Divide everything by the smallest value to see relative sizes.
Normalize: A/min : B/min : C/min
Real-World Examples
Three-part ratios appear in many contexts: mixing paint colors (red:blue:yellow), dividing profits among three partners, recipe ingredients, concrete mix ratios (cement:sand:gravel), and asset allocation in investment portfolios.
Handling Decimals
- If any of the numbers are decimals, multiply all three by a power of 10 to make them whole numbers first.
- Then find the GCD and simplify normally.
- The ratio 0.5 : 1.5 : 2.0 becomes 5 : 15 : 20 = 1 : 3 : 4.