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Finding the Fourth Proportional to 11.81, 17.72 and 9.90

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Solution

The fourth proportional to 11.81, 17.72 and 9.90 is: 14.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    11.81 : 17.72 = 9.90 : x
  2. Step 2: Convert to fraction form
    11.81/17.72 = 9.90/x
  3. Step 3: Cross multiply
    11.81x = 17.72 × 9.90
  4. Step 4: Simplify right side
    11.81x = 175.38
  5. Step 5: Solve for x
    x = 175.38/11.81
  6. Step 6: Final answer
    x = 14.86

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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.