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Finding the Fourth Proportional to 613.88, 847.42 and 392.78

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Solution

The fourth proportional to 613.88, 847.42 and 392.78 is: 542.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    613.88 : 847.42 = 392.78 : x
  2. Step 2: Convert to fraction form
    613.88/847.42 = 392.78/x
  3. Step 3: Cross multiply
    613.88x = 847.42 × 392.78
  4. Step 4: Simplify right side
    613.88x = 332,850.76
  5. Step 5: Solve for x
    x = 332,850.76/613.88
  6. Step 6: Final answer
    x = 542.21

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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.