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Finding the Fourth Proportional to 81.90, 122.81 and 41.22

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Solution

The fourth proportional to 81.90, 122.81 and 41.22 is: 61.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.90 : 122.81 = 41.22 : x
  2. Step 2: Convert to fraction form
    81.90/122.81 = 41.22/x
  3. Step 3: Cross multiply
    81.90x = 122.81 × 41.22
  4. Step 4: Simplify right side
    81.90x = 5,062.02
  5. Step 5: Solve for x
    x = 5,062.02/81.90
  6. Step 6: Final answer
    x = 61.81

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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.