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Finding the Fourth Proportional to 120.80, 166.61 and 81.44

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Solution

The fourth proportional to 120.80, 166.61 and 81.44 is: 112.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.80 : 166.61 = 81.44 : x
  2. Step 2: Convert to fraction form
    120.80/166.61 = 81.44/x
  3. Step 3: Cross multiply
    120.80x = 166.61 × 81.44
  4. Step 4: Simplify right side
    120.80x = 13,568.73
  5. Step 5: Solve for x
    x = 13,568.73/120.80
  6. Step 6: Final answer
    x = 112.33

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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.