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Finding the Fourth Proportional to 81.22, 111.83 and 68.91

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Solution

The fourth proportional to 81.22, 111.83 and 68.91 is: 94.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.22 : 111.83 = 68.91 : x
  2. Step 2: Convert to fraction form
    81.22/111.83 = 68.91/x
  3. Step 3: Cross multiply
    81.22x = 111.83 × 68.91
  4. Step 4: Simplify right side
    81.22x = 7,705.86
  5. Step 5: Solve for x
    x = 7,705.86/81.22
  6. Step 6: Final answer
    x = 94.88

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.