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Finding the Fourth Proportional to 81.33, 121.92 and 27.21

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Solution

The fourth proportional to 81.33, 121.92 and 27.21 is: 40.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.33 : 121.92 = 27.21 : x
  2. Step 2: Convert to fraction form
    81.33/121.92 = 27.21/x
  3. Step 3: Cross multiply
    81.33x = 121.92 × 27.21
  4. Step 4: Simplify right side
    81.33x = 3,317.44
  5. Step 5: Solve for x
    x = 3,317.44/81.33
  6. Step 6: Final answer
    x = 40.79

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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.