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Finding the Fourth Proportional to 81.33, 122.61 and 76.92

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Solution

The fourth proportional to 81.33, 122.61 and 76.92 is: 115.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.33 : 122.61 = 76.92 : x
  2. Step 2: Convert to fraction form
    81.33/122.61 = 76.92/x
  3. Step 3: Cross multiply
    81.33x = 122.61 × 76.92
  4. Step 4: Simplify right side
    81.33x = 9,431.16
  5. Step 5: Solve for x
    x = 9,431.16/81.33
  6. Step 6: Final answer
    x = 115.96

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.