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Finding the Fourth Proportional to 13.89, 20.82 and 12.39

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Solution

The fourth proportional to 13.89, 20.82 and 12.39 is: 18.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.89 : 20.82 = 12.39 : x
  2. Step 2: Convert to fraction form
    13.89/20.82 = 12.39/x
  3. Step 3: Cross multiply
    13.89x = 20.82 × 12.39
  4. Step 4: Simplify right side
    13.89x = 257.96
  5. Step 5: Solve for x
    x = 257.96/13.89
  6. Step 6: Final answer
    x = 18.57

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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.