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Finding the Fourth Proportional to 685.18, 1,027.78 and 425.94

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Solution

The fourth proportional to 685.18, 1,027.78 and 425.94 is: 638.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.18 : 1,027.78 = 425.94 : x
  2. Step 2: Convert to fraction form
    685.18/1,027.78 = 425.94/x
  3. Step 3: Cross multiply
    685.18x = 1,027.78 × 425.94
  4. Step 4: Simplify right side
    685.18x = 437,772.61
  5. Step 5: Solve for x
    x = 437,772.61/685.18
  6. Step 6: Final answer
    x = 638.92

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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.