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Finding the Fourth Proportional to 81.32, 121.96 and 27.19

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Solution

The fourth proportional to 81.32, 121.96 and 27.19 is: 40.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.32 : 121.96 = 27.19 : x
  2. Step 2: Convert to fraction form
    81.32/121.96 = 27.19/x
  3. Step 3: Cross multiply
    81.32x = 121.96 × 27.19
  4. Step 4: Simplify right side
    81.32x = 3,316.09
  5. Step 5: Solve for x
    x = 3,316.09/81.32
  6. Step 6: Final answer
    x = 40.78

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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.