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Finding the Fourth Proportional to 425.78, 638.60 and 165.90

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Solution

The fourth proportional to 425.78, 638.60 and 165.90 is: 248.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    425.78 : 638.60 = 165.90 : x
  2. Step 2: Convert to fraction form
    425.78/638.60 = 165.90/x
  3. Step 3: Cross multiply
    425.78x = 638.60 × 165.90
  4. Step 4: Simplify right side
    425.78x = 105,942.91
  5. Step 5: Solve for x
    x = 105,942.91/425.78
  6. Step 6: Final answer
    x = 248.82

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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.