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Finding the Fourth Proportional to 399.78, 551.52 and 257.92

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Solution

The fourth proportional to 399.78, 551.52 and 257.92 is: 355.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    399.78 : 551.52 = 257.92 : x
  2. Step 2: Convert to fraction form
    399.78/551.52 = 257.92/x
  3. Step 3: Cross multiply
    399.78x = 551.52 × 257.92
  4. Step 4: Simplify right side
    399.78x = 142,246.66
  5. Step 5: Solve for x
    x = 142,246.66/399.78
  6. Step 6: Final answer
    x = 355.81

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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.