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Finding the Fourth Proportional to 425.67, 638.55 and 391.86

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Solution

The fourth proportional to 425.67, 638.55 and 391.86 is: 587.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.67 : 638.55 = 391.86 : x
  2. Step 2: Convert to fraction form
    425.67/638.55 = 391.86/x
  3. Step 3: Cross multiply
    425.67x = 638.55 × 391.86
  4. Step 4: Simplify right side
    425.67x = 250,222.20
  5. Step 5: Solve for x
    x = 250,222.20/425.67
  6. Step 6: Final answer
    x = 587.83

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.