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Finding the Fourth Proportional to 138.11, 207.56 and 99.66

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Solution

The fourth proportional to 138.11, 207.56 and 99.66 is: 149.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.11 : 207.56 = 99.66 : x
  2. Step 2: Convert to fraction form
    138.11/207.56 = 99.66/x
  3. Step 3: Cross multiply
    138.11x = 207.56 × 99.66
  4. Step 4: Simplify right side
    138.11x = 20,684.71
  5. Step 5: Solve for x
    x = 20,684.71/138.11
  6. Step 6: Final answer
    x = 149.78

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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.