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Finding the Fourth Proportional to 686.37, 947.29 and 391.68

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Solution

The fourth proportional to 686.37, 947.29 and 391.68 is: 540.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.37 : 947.29 = 391.68 : x
  2. Step 2: Convert to fraction form
    686.37/947.29 = 391.68/x
  3. Step 3: Cross multiply
    686.37x = 947.29 × 391.68
  4. Step 4: Simplify right side
    686.37x = 371,034.96
  5. Step 5: Solve for x
    x = 371,034.96/686.37
  6. Step 6: Final answer
    x = 540.58

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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.