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Finding the Fourth Proportional to 391.29, 539.82 and 280.55

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Solution

The fourth proportional to 391.29, 539.82 and 280.55 is: 387.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.29 : 539.82 = 280.55 : x
  2. Step 2: Convert to fraction form
    391.29/539.82 = 280.55/x
  3. Step 3: Cross multiply
    391.29x = 539.82 × 280.55
  4. Step 4: Simplify right side
    391.29x = 151,443.80
  5. Step 5: Solve for x
    x = 151,443.80/391.29
  6. Step 6: Final answer
    x = 387.04

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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.