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Finding the Fourth Proportional to 311.20, 429.12 and 255.76

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Solution

The fourth proportional to 311.20, 429.12 and 255.76 is: 352.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.20 : 429.12 = 255.76 : x
  2. Step 2: Convert to fraction form
    311.20/429.12 = 255.76/x
  3. Step 3: Cross multiply
    311.20x = 429.12 × 255.76
  4. Step 4: Simplify right side
    311.20x = 109,751.73
  5. Step 5: Solve for x
    x = 109,751.73/311.20
  6. Step 6: Final answer
    x = 352.67

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.