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Finding the Fourth Proportional to 139.31, 192.25 and 81.09

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Solution

The fourth proportional to 139.31, 192.25 and 81.09 is: 111.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.31 : 192.25 = 81.09 : x
  2. Step 2: Convert to fraction form
    139.31/192.25 = 81.09/x
  3. Step 3: Cross multiply
    139.31x = 192.25 × 81.09
  4. Step 4: Simplify right side
    139.31x = 15,589.55
  5. Step 5: Solve for x
    x = 15,589.55/139.31
  6. Step 6: Final answer
    x = 111.91

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.