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Finding the Fourth Proportional to 12.39, 18.56 and 9.15

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Solution

The fourth proportional to 12.39, 18.56 and 9.15 is: 13.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.39 : 18.56 = 9.15 : x
  2. Step 2: Convert to fraction form
    12.39/18.56 = 9.15/x
  3. Step 3: Cross multiply
    12.39x = 18.56 × 9.15
  4. Step 4: Simplify right side
    12.39x = 169.78
  5. Step 5: Solve for x
    x = 169.78/12.39
  6. Step 6: Final answer
    x = 13.71

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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.