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Finding the Fourth Proportional to 81.26, 121.14 and 76.66

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Solution

The fourth proportional to 81.26, 121.14 and 76.66 is: 114.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.26 : 121.14 = 76.66 : x
  2. Step 2: Convert to fraction form
    81.26/121.14 = 76.66/x
  3. Step 3: Cross multiply
    81.26x = 121.14 × 76.66
  4. Step 4: Simplify right side
    81.26x = 9,286.59
  5. Step 5: Solve for x
    x = 9,286.59/81.26
  6. Step 6: Final answer
    x = 114.28

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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.