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Finding the Fourth Proportional to 81.41, 122.68 and 80.70

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Solution

The fourth proportional to 81.41, 122.68 and 80.70 is: 121.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.41 : 122.68 = 80.70 : x
  2. Step 2: Convert to fraction form
    81.41/122.68 = 80.70/x
  3. Step 3: Cross multiply
    81.41x = 122.68 × 80.70
  4. Step 4: Simplify right side
    81.41x = 9,899.92
  5. Step 5: Solve for x
    x = 9,899.92/81.41
  6. Step 6: Final answer
    x = 121.61

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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.