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Finding the Fourth Proportional to 391.71, 587.60 and 131.78

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Solution

The fourth proportional to 391.71, 587.60 and 131.78 is: 197.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.71 : 587.60 = 131.78 : x
  2. Step 2: Convert to fraction form
    391.71/587.60 = 131.78/x
  3. Step 3: Cross multiply
    391.71x = 587.60 × 131.78
  4. Step 4: Simplify right side
    391.71x = 77,432.67
  5. Step 5: Solve for x
    x = 77,432.67/391.71
  6. Step 6: Final answer
    x = 197.68

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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.