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Finding the Fourth Proportional to 81.48, 122.41 and 76.87

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Solution

The fourth proportional to 81.48, 122.41 and 76.87 is: 115.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.48 : 122.41 = 76.87 : x
  2. Step 2: Convert to fraction form
    81.48/122.41 = 76.87/x
  3. Step 3: Cross multiply
    81.48x = 122.41 × 76.87
  4. Step 4: Simplify right side
    81.48x = 9,410.25
  5. Step 5: Solve for x
    x = 9,410.25/81.48
  6. Step 6: Final answer
    x = 115.49

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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.