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Finding the Fourth Proportional to 411.72, 618.40 and 257.92

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Solution

The fourth proportional to 411.72, 618.40 and 257.92 is: 387.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    411.72 : 618.40 = 257.92 : x
  2. Step 2: Convert to fraction form
    411.72/618.40 = 257.92/x
  3. Step 3: Cross multiply
    411.72x = 618.40 × 257.92
  4. Step 4: Simplify right side
    411.72x = 159,497.73
  5. Step 5: Solve for x
    x = 159,497.73/411.72
  6. Step 6: Final answer
    x = 387.39

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.