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Finding the Fourth Proportional to 138.41, 207.86 and 76.69

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Solution

The fourth proportional to 138.41, 207.86 and 76.69 is: 115.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.41 : 207.86 = 76.69 : x
  2. Step 2: Convert to fraction form
    138.41/207.86 = 76.69/x
  3. Step 3: Cross multiply
    138.41x = 207.86 × 76.69
  4. Step 4: Simplify right side
    138.41x = 15,940.78
  5. Step 5: Solve for x
    x = 15,940.78/138.41
  6. Step 6: Final answer
    x = 115.17

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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.