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Finding the Fourth Proportional to 391.27, 539.40 and 280.55

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Solution

The fourth proportional to 391.27, 539.40 and 280.55 is: 386.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.27 : 539.40 = 280.55 : x
  2. Step 2: Convert to fraction form
    391.27/539.40 = 280.55/x
  3. Step 3: Cross multiply
    391.27x = 539.40 × 280.55
  4. Step 4: Simplify right side
    391.27x = 151,325.97
  5. Step 5: Solve for x
    x = 151,325.97/391.27
  6. Step 6: Final answer
    x = 386.76

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.