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Finding the Fourth Proportional to 12.39, 18.58 and 7.89

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Solution

The fourth proportional to 12.39, 18.58 and 7.89 is: 11.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.39 : 18.58 = 7.89 : x
  2. Step 2: Convert to fraction form
    12.39/18.58 = 7.89/x
  3. Step 3: Cross multiply
    12.39x = 18.58 × 7.89
  4. Step 4: Simplify right side
    12.39x = 146.60
  5. Step 5: Solve for x
    x = 146.60/12.39
  6. Step 6: Final answer
    x = 11.83

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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.