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Finding the Fourth Proportional to 11.91, 17.87 and 7.90

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Solution

The fourth proportional to 11.91, 17.87 and 7.90 is: 11.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    11.91 : 17.87 = 7.90 : x
  2. Step 2: Convert to fraction form
    11.91/17.87 = 7.90/x
  3. Step 3: Cross multiply
    11.91x = 17.87 × 7.90
  4. Step 4: Simplify right side
    11.91x = 141.13
  5. Step 5: Solve for x
    x = 141.13/11.91
  6. Step 6: Final answer
    x = 11.85

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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.