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Finding the Fourth Proportional to 391.25, 586.81 and 131.20

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Solution

The fourth proportional to 391.25, 586.81 and 131.20 is: 196.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.25 : 586.81 = 131.20 : x
  2. Step 2: Convert to fraction form
    391.25/586.81 = 131.20/x
  3. Step 3: Cross multiply
    391.25x = 586.81 × 131.20
  4. Step 4: Simplify right side
    391.25x = 76,991.47
  5. Step 5: Solve for x
    x = 76,991.47/391.25
  6. Step 6: Final answer
    x = 196.78

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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.