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Finding the Fourth Proportional to 138.09, 190.31 and 115.92

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Solution

The fourth proportional to 138.09, 190.31 and 115.92 is: 159.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.09 : 190.31 = 115.92 : x
  2. Step 2: Convert to fraction form
    138.09/190.31 = 115.92/x
  3. Step 3: Cross multiply
    138.09x = 190.31 × 115.92
  4. Step 4: Simplify right side
    138.09x = 22,060.74
  5. Step 5: Solve for x
    x = 22,060.74/138.09
  6. Step 6: Final answer
    x = 159.76

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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.