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Finding the Fourth Proportional to 617.90, 853.02 and 491.61

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Solution

The fourth proportional to 617.90, 853.02 and 491.61 is: 678.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    617.90 : 853.02 = 491.61 : x
  2. Step 2: Convert to fraction form
    617.90/853.02 = 491.61/x
  3. Step 3: Cross multiply
    617.90x = 853.02 × 491.61
  4. Step 4: Simplify right side
    617.90x = 419,353.16
  5. Step 5: Solve for x
    x = 419,353.16/617.90
  6. Step 6: Final answer
    x = 678.68

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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.