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Finding the Fourth Proportional to 81.06, 121.59 and 42.60

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Solution

The fourth proportional to 81.06, 121.59 and 42.60 is: 63.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.06 : 121.59 = 42.60 : x
  2. Step 2: Convert to fraction form
    81.06/121.59 = 42.60/x
  3. Step 3: Cross multiply
    81.06x = 121.59 × 42.60
  4. Step 4: Simplify right side
    81.06x = 5,179.73
  5. Step 5: Solve for x
    x = 5,179.73/81.06
  6. Step 6: Final answer
    x = 63.90

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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.