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Finding the Fourth Proportional to 686.76, 1,028.96 and 339.62

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Solution

The fourth proportional to 686.76, 1,028.96 and 339.62 is: 508.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.76 : 1,028.96 = 339.62 : x
  2. Step 2: Convert to fraction form
    686.76/1,028.96 = 339.62/x
  3. Step 3: Cross multiply
    686.76x = 1,028.96 × 339.62
  4. Step 4: Simplify right side
    686.76x = 349,455.40
  5. Step 5: Solve for x
    x = 349,455.40/686.76
  6. Step 6: Final answer
    x = 508.85

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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.