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Finding the Fourth Proportional to 11.81, 17.68 and 7.81

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Solution

The fourth proportional to 11.81, 17.68 and 7.81 is: 11.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    11.81 : 17.68 = 7.81 : x
  2. Step 2: Convert to fraction form
    11.81/17.68 = 7.81/x
  3. Step 3: Cross multiply
    11.81x = 17.68 × 7.81
  4. Step 4: Simplify right side
    11.81x = 138.08
  5. Step 5: Solve for x
    x = 138.08/11.81
  6. Step 6: Final answer
    x = 11.69

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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.