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Finding the Fourth Proportional to 392.11, 539.92 and 318.30

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Solution

The fourth proportional to 392.11, 539.92 and 318.30 is: 438.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    392.11 : 539.92 = 318.30 : x
  2. Step 2: Convert to fraction form
    392.11/539.92 = 318.30/x
  3. Step 3: Cross multiply
    392.11x = 539.92 × 318.30
  4. Step 4: Simplify right side
    392.11x = 171,856.54
  5. Step 5: Solve for x
    x = 171,856.54/392.11
  6. Step 6: Final answer
    x = 438.29

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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.