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Finding the Fourth Proportional to 391.28, 539.76 and 243.68

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Solution

The fourth proportional to 391.28, 539.76 and 243.68 is: 336.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.28 : 539.76 = 243.68 : x
  2. Step 2: Convert to fraction form
    391.28/539.76 = 243.68/x
  3. Step 3: Cross multiply
    391.28x = 539.76 × 243.68
  4. Step 4: Simplify right side
    391.28x = 131,528.72
  5. Step 5: Solve for x
    x = 131,528.72/391.28
  6. Step 6: Final answer
    x = 336.15

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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.