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Finding the Fourth Proportional to 138.52, 207.78 and 61.42

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Solution

The fourth proportional to 138.52, 207.78 and 61.42 is: 92.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.52 : 207.78 = 61.42 : x
  2. Step 2: Convert to fraction form
    138.52/207.78 = 61.42/x
  3. Step 3: Cross multiply
    138.52x = 207.78 × 61.42
  4. Step 4: Simplify right side
    138.52x = 12,761.85
  5. Step 5: Solve for x
    x = 12,761.85/138.52
  6. Step 6: Final answer
    x = 92.13

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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.