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Finding the Fourth Proportional to 624.28, 861.78 and 391.72

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Solution

The fourth proportional to 624.28, 861.78 and 391.72 is: 540.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    624.28 : 861.78 = 391.72 : x
  2. Step 2: Convert to fraction form
    624.28/861.78 = 391.72/x
  3. Step 3: Cross multiply
    624.28x = 861.78 × 391.72
  4. Step 4: Simplify right side
    624.28x = 337,576.46
  5. Step 5: Solve for x
    x = 337,576.46/624.28
  6. Step 6: Final answer
    x = 540.75

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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.