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Finding the Fourth Proportional to 81.27, 121.09 and 75.75

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Solution

The fourth proportional to 81.27, 121.09 and 75.75 is: 112.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.27 : 121.09 = 75.75 : x
  2. Step 2: Convert to fraction form
    81.27/121.09 = 75.75/x
  3. Step 3: Cross multiply
    81.27x = 121.09 × 75.75
  4. Step 4: Simplify right side
    81.27x = 9,172.38
  5. Step 5: Solve for x
    x = 9,172.38/81.27
  6. Step 6: Final answer
    x = 112.86

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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.