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Finding the Fourth Proportional to 408.78, 612.60 and 271.20

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Solution

The fourth proportional to 408.78, 612.60 and 271.20 is: 406.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.78 : 612.60 = 271.20 : x
  2. Step 2: Convert to fraction form
    408.78/612.60 = 271.20/x
  3. Step 3: Cross multiply
    408.78x = 612.60 × 271.20
  4. Step 4: Simplify right side
    408.78x = 166,137.12
  5. Step 5: Solve for x
    x = 166,137.12/408.78
  6. Step 6: Final answer
    x = 406.42

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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.