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Finding the Fourth Proportional to 618.90, 853.59 and 397.86

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Solution

The fourth proportional to 618.90, 853.59 and 397.86 is: 548.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    618.90 : 853.59 = 397.86 : x
  2. Step 2: Convert to fraction form
    618.90/853.59 = 397.86/x
  3. Step 3: Cross multiply
    618.90x = 853.59 × 397.86
  4. Step 4: Simplify right side
    618.90x = 339,609.32
  5. Step 5: Solve for x
    x = 339,609.32/618.90
  6. Step 6: Final answer
    x = 548.73

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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.