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Finding the Fourth Proportional to 391.28, 539.40 and 347.56

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Solution

The fourth proportional to 391.28, 539.40 and 347.56 is: 479.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.28 : 539.40 = 347.56 : x
  2. Step 2: Convert to fraction form
    391.28/539.40 = 347.56/x
  3. Step 3: Cross multiply
    391.28x = 539.40 × 347.56
  4. Step 4: Simplify right side
    391.28x = 187,473.86
  5. Step 5: Solve for x
    x = 187,473.86/391.28
  6. Step 6: Final answer
    x = 479.13

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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.