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Finding the Fourth Proportional to 81.55, 122.96 and 80.54

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Solution

The fourth proportional to 81.55, 122.96 and 80.54 is: 121.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.55 : 122.96 = 80.54 : x
  2. Step 2: Convert to fraction form
    81.55/122.96 = 80.54/x
  3. Step 3: Cross multiply
    81.55x = 122.96 × 80.54
  4. Step 4: Simplify right side
    81.55x = 9,903.20
  5. Step 5: Solve for x
    x = 9,903.20/81.55
  6. Step 6: Final answer
    x = 121.44

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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.