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Finding the Fourth Proportional to 138.27, 207.81 and 128.22

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Solution

The fourth proportional to 138.27, 207.81 and 128.22 is: 192.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.27 : 207.81 = 128.22 : x
  2. Step 2: Convert to fraction form
    138.27/207.81 = 128.22/x
  3. Step 3: Cross multiply
    138.27x = 207.81 × 128.22
  4. Step 4: Simplify right side
    138.27x = 26,645.40
  5. Step 5: Solve for x
    x = 26,645.40/138.27
  6. Step 6: Final answer
    x = 192.71

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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.