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Finding the Fourth Proportional to 138.43, 207.63 and 80.69

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Solution

The fourth proportional to 138.43, 207.63 and 80.69 is: 121.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.43 : 207.63 = 80.69 : x
  2. Step 2: Convert to fraction form
    138.43/207.63 = 80.69/x
  3. Step 3: Cross multiply
    138.43x = 207.63 × 80.69
  4. Step 4: Simplify right side
    138.43x = 16,753.66
  5. Step 5: Solve for x
    x = 16,753.66/138.43
  6. Step 6: Final answer
    x = 121.03

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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.