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Finding the Fourth Proportional to 81.52, 122.61 and 80.71

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Solution

The fourth proportional to 81.52, 122.61 and 80.71 is: 121.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.52 : 122.61 = 80.71 : x
  2. Step 2: Convert to fraction form
    81.52/122.61 = 80.71/x
  3. Step 3: Cross multiply
    81.52x = 122.61 × 80.71
  4. Step 4: Simplify right side
    81.52x = 9,895.85
  5. Step 5: Solve for x
    x = 9,895.85/81.52
  6. Step 6: Final answer
    x = 121.39

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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.