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Finding the Fourth Proportional to 81.22, 122.86 and 80.68

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Solution

The fourth proportional to 81.22, 122.86 and 80.68 is: 122.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.22 : 122.86 = 80.68 : x
  2. Step 2: Convert to fraction form
    81.22/122.86 = 80.68/x
  3. Step 3: Cross multiply
    81.22x = 122.86 × 80.68
  4. Step 4: Simplify right side
    81.22x = 9,912.34
  5. Step 5: Solve for x
    x = 9,912.34/81.22
  6. Step 6: Final answer
    x = 122.04

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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.