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Finding the Fourth Proportional to 81.89, 122.81 and 76.50

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Solution

The fourth proportional to 81.89, 122.81 and 76.50 is: 114.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.89 : 122.81 = 76.50 : x
  2. Step 2: Convert to fraction form
    81.89/122.81 = 76.50/x
  3. Step 3: Cross multiply
    81.89x = 122.81 × 76.50
  4. Step 4: Simplify right side
    81.89x = 9,395.01
  5. Step 5: Solve for x
    x = 9,395.01/81.89
  6. Step 6: Final answer
    x = 114.72

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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.