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Finding the Fourth Proportional to 391.86, 587.81 and 131.86

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Solution

The fourth proportional to 391.86, 587.81 and 131.86 is: 197.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.86 : 587.81 = 131.86 : x
  2. Step 2: Convert to fraction form
    391.86/587.81 = 131.86/x
  3. Step 3: Cross multiply
    391.86x = 587.81 × 131.86
  4. Step 4: Simplify right side
    391.86x = 77,507.65
  5. Step 5: Solve for x
    x = 77,507.65/391.86
  6. Step 6: Final answer
    x = 197.80

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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.