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Finding the Fourth Proportional to 138.28, 207.39 and 47

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Solution

The fourth proportional to 138.28, 207.39 and 47 is: 70.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.28 : 207.39 = 47 : x
  2. Step 2: Convert to fraction form
    138.28/207.39 = 47/x
  3. Step 3: Cross multiply
    138.28x = 207.39 × 47
  4. Step 4: Simplify right side
    138.28x = 9,747.33
  5. Step 5: Solve for x
    x = 9,747.33/138.28
  6. Step 6: Final answer
    x = 70.49

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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.