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Finding the Fourth Proportional to 18.82, 28.20 and 12.39

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Solution

The fourth proportional to 18.82, 28.20 and 12.39 is: 18.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.82 : 28.20 = 12.39 : x
  2. Step 2: Convert to fraction form
    18.82/28.20 = 12.39/x
  3. Step 3: Cross multiply
    18.82x = 28.20 × 12.39
  4. Step 4: Simplify right side
    18.82x = 349.40
  5. Step 5: Solve for x
    x = 349.40/18.82
  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.