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Finding the Fourth Proportional to 391.86, 587.79 and 131.81

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Solution

The fourth proportional to 391.86, 587.79 and 131.81 is: 197.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.86 : 587.79 = 131.81 : x
  2. Step 2: Convert to fraction form
    391.86/587.79 = 131.81/x
  3. Step 3: Cross multiply
    391.86x = 587.79 × 131.81
  4. Step 4: Simplify right side
    391.86x = 77,476.60
  5. Step 5: Solve for x
    x = 77,476.60/391.86
  6. Step 6: Final answer
    x = 197.72

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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.