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Finding the Fourth Proportional to 397.31, 548.20 and 239.90

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Solution

The fourth proportional to 397.31, 548.20 and 239.90 is: 331.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    397.31 : 548.20 = 239.90 : x
  2. Step 2: Convert to fraction form
    397.31/548.20 = 239.90/x
  3. Step 3: Cross multiply
    397.31x = 548.20 × 239.90
  4. Step 4: Simplify right side
    397.31x = 131,510.74
  5. Step 5: Solve for x
    x = 131,510.74/397.31
  6. Step 6: Final answer
    x = 331.01

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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.