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Finding the Fourth Proportional to 618.90, 853.97 and 397.80

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Solution

The fourth proportional to 618.90, 853.97 and 397.80 is: 548.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    618.90 : 853.97 = 397.80 : x
  2. Step 2: Convert to fraction form
    618.90/853.97 = 397.80/x
  3. Step 3: Cross multiply
    618.90x = 853.97 × 397.80
  4. Step 4: Simplify right side
    618.90x = 339,709.27
  5. Step 5: Solve for x
    x = 339,709.27/618.90
  6. Step 6: Final answer
    x = 548.89

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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.