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Finding the Fourth Proportional to 120.94, 166.78 and 81.61

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Solution

The fourth proportional to 120.94, 166.78 and 81.61 is: 112.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.94 : 166.78 = 81.61 : x
  2. Step 2: Convert to fraction form
    120.94/166.78 = 81.61/x
  3. Step 3: Cross multiply
    120.94x = 166.78 × 81.61
  4. Step 4: Simplify right side
    120.94x = 13,610.60
  5. Step 5: Solve for x
    x = 13,610.60/120.94
  6. Step 6: Final answer
    x = 112.54

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.