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Finding the Fourth Proportional to 391.64, 539.92 and 280.92

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Solution

The fourth proportional to 391.64, 539.92 and 280.92 is: 387.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.64 : 539.92 = 280.92 : x
  2. Step 2: Convert to fraction form
    391.64/539.92 = 280.92/x
  3. Step 3: Cross multiply
    391.64x = 539.92 × 280.92
  4. Step 4: Simplify right side
    391.64x = 151,674.33
  5. Step 5: Solve for x
    x = 151,674.33/391.64
  6. Step 6: Final answer
    x = 387.28

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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.