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Finding the Fourth Proportional to 686.52, 947.31 and 391.71

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Solution

The fourth proportional to 686.52, 947.31 and 391.71 is: 540.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.52 : 947.31 = 391.71 : x
  2. Step 2: Convert to fraction form
    686.52/947.31 = 391.71/x
  3. Step 3: Cross multiply
    686.52x = 947.31 × 391.71
  4. Step 4: Simplify right side
    686.52x = 371,070.80
  5. Step 5: Solve for x
    x = 371,070.80/686.52
  6. Step 6: Final answer
    x = 540.51

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.