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Finding the Fourth Proportional to 18.92, 28.40 and 12.88

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Solution

The fourth proportional to 18.92, 28.40 and 12.88 is: 19.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.92 : 28.40 = 12.88 : x
  2. Step 2: Convert to fraction form
    18.92/28.40 = 12.88/x
  3. Step 3: Cross multiply
    18.92x = 28.40 × 12.88
  4. Step 4: Simplify right side
    18.92x = 365.79
  5. Step 5: Solve for x
    x = 365.79/18.92
  6. Step 6: Final answer
    x = 19.33

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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.