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Finding the Fourth Proportional to 686.78, 1,027.89 and 426.47

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Solution

The fourth proportional to 686.78, 1,027.89 and 426.47 is: 638.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.78 : 1,027.89 = 426.47 : x
  2. Step 2: Convert to fraction form
    686.78/1,027.89 = 426.47/x
  3. Step 3: Cross multiply
    686.78x = 1,027.89 × 426.47
  4. Step 4: Simplify right side
    686.78x = 438,359.11
  5. Step 5: Solve for x
    x = 438,359.11/686.78
  6. Step 6: Final answer
    x = 638.28

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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.