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Finding the Fourth Proportional to 138.97, 207.30 and 129.15

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Solution

The fourth proportional to 138.97, 207.30 and 129.15 is: 192.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.97 : 207.30 = 129.15 : x
  2. Step 2: Convert to fraction form
    138.97/207.30 = 129.15/x
  3. Step 3: Cross multiply
    138.97x = 207.30 × 129.15
  4. Step 4: Simplify right side
    138.97x = 26,772.80
  5. Step 5: Solve for x
    x = 26,772.80/138.97
  6. Step 6: Final answer
    x = 192.65

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.