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Finding the Fourth Proportional to 391.87, 539.94 and 280.99

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Solution

The fourth proportional to 391.87, 539.94 and 280.99 is: 387.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.87 : 539.94 = 280.99 : x
  2. Step 2: Convert to fraction form
    391.87/539.94 = 280.99/x
  3. Step 3: Cross multiply
    391.87x = 539.94 × 280.99
  4. Step 4: Simplify right side
    391.87x = 151,717.74
  5. Step 5: Solve for x
    x = 151,717.74/391.87
  6. Step 6: Final answer
    x = 387.16

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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.