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Finding the Fourth Proportional to 397.47, 548.45 and 257.78

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Solution

The fourth proportional to 397.47, 548.45 and 257.78 is: 355.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    397.47 : 548.45 = 257.78 : x
  2. Step 2: Convert to fraction form
    397.47/548.45 = 257.78/x
  3. Step 3: Cross multiply
    397.47x = 548.45 × 257.78
  4. Step 4: Simplify right side
    397.47x = 141,380.49
  5. Step 5: Solve for x
    x = 141,380.49/397.47
  6. Step 6: Final answer
    x = 355.70

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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.