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Finding the Fourth Proportional to 686.49, 1,028.87 and 439.60

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Solution

The fourth proportional to 686.49, 1,028.87 and 439.60 is: 658.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.49 : 1,028.87 = 439.60 : x
  2. Step 2: Convert to fraction form
    686.49/1,028.87 = 439.60/x
  3. Step 3: Cross multiply
    686.49x = 1,028.87 × 439.60
  4. Step 4: Simplify right side
    686.49x = 452,291.25
  5. Step 5: Solve for x
    x = 452,291.25/686.49
  6. Step 6: Final answer
    x = 658.85

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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.