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Finding the Fourth Proportional to 686.17, 946.87 and 391.47

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Solution

The fourth proportional to 686.17, 946.87 and 391.47 is: 540.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.17 : 946.87 = 391.47 : x
  2. Step 2: Convert to fraction form
    686.17/946.87 = 391.47/x
  3. Step 3: Cross multiply
    686.17x = 946.87 × 391.47
  4. Step 4: Simplify right side
    686.17x = 370,671.20
  5. Step 5: Solve for x
    x = 370,671.20/686.17
  6. Step 6: Final answer
    x = 540.20

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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.