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Finding the Fourth Proportional to 611.61, 917.20 and 391.92

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Solution

The fourth proportional to 611.61, 917.20 and 391.92 is: 587.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.61 : 917.20 = 391.92 : x
  2. Step 2: Convert to fraction form
    611.61/917.20 = 391.92/x
  3. Step 3: Cross multiply
    611.61x = 917.20 × 391.92
  4. Step 4: Simplify right side
    611.61x = 359,469.02
  5. Step 5: Solve for x
    x = 359,469.02/611.61
  6. Step 6: Final answer
    x = 587.74

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.