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Finding the Fourth Proportional to 81.58, 122.20 and 68.82

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Solution

The fourth proportional to 81.58, 122.20 and 68.82 is: 103.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.58 : 122.20 = 68.82 : x
  2. Step 2: Convert to fraction form
    81.58/122.20 = 68.82/x
  3. Step 3: Cross multiply
    81.58x = 122.20 × 68.82
  4. Step 4: Simplify right side
    81.58x = 8,409.80
  5. Step 5: Solve for x
    x = 8,409.80/81.58
  6. Step 6: Final answer
    x = 103.09

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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.