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Finding the Fourth Proportional to 20.54, 30.81 and 12.43

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Solution

The fourth proportional to 20.54, 30.81 and 12.43 is: 18.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.54 : 30.81 = 12.43 : x
  2. Step 2: Convert to fraction form
    20.54/30.81 = 12.43/x
  3. Step 3: Cross multiply
    20.54x = 30.81 × 12.43
  4. Step 4: Simplify right side
    20.54x = 382.89
  5. Step 5: Solve for x
    x = 382.89/20.54
  6. Step 6: Final answer
    x = 18.65

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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.