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Finding the Fourth Proportional to 686.68, 1,028.90 and 321.17

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Solution

The fourth proportional to 686.68, 1,028.90 and 321.17 is: 481.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.68 : 1,028.90 = 321.17 : x
  2. Step 2: Convert to fraction form
    686.68/1,028.90 = 321.17/x
  3. Step 3: Cross multiply
    686.68x = 1,028.90 × 321.17
  4. Step 4: Simplify right side
    686.68x = 330,447.47
  5. Step 5: Solve for x
    x = 330,447.47/686.68
  6. Step 6: Final answer
    x = 481.23

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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.