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Finding the Fourth Proportional to 618.61, 853.78 and 397.55

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Solution

The fourth proportional to 618.61, 853.78 and 397.55 is: 548.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    618.61 : 853.78 = 397.55 : x
  2. Step 2: Convert to fraction form
    618.61/853.78 = 397.55/x
  3. Step 3: Cross multiply
    618.61x = 853.78 × 397.55
  4. Step 4: Simplify right side
    618.61x = 339,420.24
  5. Step 5: Solve for x
    x = 339,420.24/618.61
  6. Step 6: Final answer
    x = 548.68

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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.