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Finding the Fourth Proportional to 81.16, 121.75 and 76.61

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Solution

The fourth proportional to 81.16, 121.75 and 76.61 is: 114.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.16 : 121.75 = 76.61 : x
  2. Step 2: Convert to fraction form
    81.16/121.75 = 76.61/x
  3. Step 3: Cross multiply
    81.16x = 121.75 × 76.61
  4. Step 4: Simplify right side
    81.16x = 9,327.38
  5. Step 5: Solve for x
    x = 9,327.38/81.16
  6. Step 6: Final answer
    x = 114.93

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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.