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Finding the Fourth Proportional to 81.82, 122.72 and 68.38

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Solution

The fourth proportional to 81.82, 122.72 and 68.38 is: 102.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.82 : 122.72 = 68.38 : x
  2. Step 2: Convert to fraction form
    81.82/122.72 = 68.38/x
  3. Step 3: Cross multiply
    81.82x = 122.72 × 68.38
  4. Step 4: Simplify right side
    81.82x = 8,391.59
  5. Step 5: Solve for x
    x = 8,391.59/81.82
  6. Step 6: Final answer
    x = 102.56

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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.