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Finding the Fourth Proportional to 391.20, 539.36 and 274.80

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Solution

The fourth proportional to 391.20, 539.36 and 274.80 is: 378.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.20 : 539.36 = 274.80 : x
  2. Step 2: Convert to fraction form
    391.20/539.36 = 274.80/x
  3. Step 3: Cross multiply
    391.20x = 539.36 × 274.80
  4. Step 4: Simplify right side
    391.20x = 148,216.13
  5. Step 5: Solve for x
    x = 148,216.13/391.20
  6. Step 6: Final answer
    x = 378.88

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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.