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Finding the Fourth Proportional to 20.20, 30.31 and 15.39

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Solution

The fourth proportional to 20.20, 30.31 and 15.39 is: 23.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.20 : 30.31 = 15.39 : x
  2. Step 2: Convert to fraction form
    20.20/30.31 = 15.39/x
  3. Step 3: Cross multiply
    20.20x = 30.31 × 15.39
  4. Step 4: Simplify right side
    20.20x = 466.47
  5. Step 5: Solve for x
    x = 466.47/20.20
  6. Step 6: Final answer
    x = 23.09

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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.