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Finding the Fourth Proportional to 81.71, 122.79 and 76.36

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Solution

The fourth proportional to 81.71, 122.79 and 76.36 is: 114.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.71 : 122.79 = 76.36 : x
  2. Step 2: Convert to fraction form
    81.71/122.79 = 76.36/x
  3. Step 3: Cross multiply
    81.71x = 122.79 × 76.36
  4. Step 4: Simplify right side
    81.71x = 9,375.75
  5. Step 5: Solve for x
    x = 9,375.75/81.71
  6. Step 6: Final answer
    x = 114.75

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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.