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Finding the Fourth Proportional to 12.13, 18.15 and 7.85

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Solution

The fourth proportional to 12.13, 18.15 and 7.85 is: 11.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.13 : 18.15 = 7.85 : x
  2. Step 2: Convert to fraction form
    12.13/18.15 = 7.85/x
  3. Step 3: Cross multiply
    12.13x = 18.15 × 7.85
  4. Step 4: Simplify right side
    12.13x = 142.48
  5. Step 5: Solve for x
    x = 142.48/12.13
  6. Step 6: Final answer
    x = 11.75

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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.