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Finding the Fourth Proportional to 686.76, 1,029.62 and 321.29

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Solution

The fourth proportional to 686.76, 1,029.62 and 321.29 is: 481.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.76 : 1,029.62 = 321.29 : x
  2. Step 2: Convert to fraction form
    686.76/1,029.62 = 321.29/x
  3. Step 3: Cross multiply
    686.76x = 1,029.62 × 321.29
  4. Step 4: Simplify right side
    686.76x = 330,799.86
  5. Step 5: Solve for x
    x = 330,799.86/686.76
  6. Step 6: Final answer
    x = 481.68

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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.