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Finding the Fourth Proportional to 28.38, 39.12 and 20.18

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Solution

The fourth proportional to 28.38, 39.12 and 20.18 is: 27.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.38 : 39.12 = 20.18 : x
  2. Step 2: Convert to fraction form
    28.38/39.12 = 20.18/x
  3. Step 3: Cross multiply
    28.38x = 39.12 × 20.18
  4. Step 4: Simplify right side
    28.38x = 789.15
  5. Step 5: Solve for x
    x = 789.15/28.38
  6. Step 6: Final answer
    x = 27.81

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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.