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Finding the Fourth Proportional to 81.77, 122.15 and 68.09

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Solution

The fourth proportional to 81.77, 122.15 and 68.09 is: 101.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.77 : 122.15 = 68.09 : x
  2. Step 2: Convert to fraction form
    81.77/122.15 = 68.09/x
  3. Step 3: Cross multiply
    81.77x = 122.15 × 68.09
  4. Step 4: Simplify right side
    81.77x = 8,316.75
  5. Step 5: Solve for x
    x = 8,316.75/81.77
  6. Step 6: Final answer
    x = 101.72

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.