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Finding the Fourth Proportional to 391.67, 539.87 and 308.64

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Solution

The fourth proportional to 391.67, 539.87 and 308.64 is: 425.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.67 : 539.87 = 308.64 : x
  2. Step 2: Convert to fraction form
    391.67/539.87 = 308.64/x
  3. Step 3: Cross multiply
    391.67x = 539.87 × 308.64
  4. Step 4: Simplify right side
    391.67x = 166,623.93
  5. Step 5: Solve for x
    x = 166,623.93/391.67
  6. Step 6: Final answer
    x = 425.42

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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.