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Finding the Fourth Proportional to 13.88, 20.81 and 6.66

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Solution

The fourth proportional to 13.88, 20.81 and 6.66 is: 9.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.88 : 20.81 = 6.66 : x
  2. Step 2: Convert to fraction form
    13.88/20.81 = 6.66/x
  3. Step 3: Cross multiply
    13.88x = 20.81 × 6.66
  4. Step 4: Simplify right side
    13.88x = 138.56
  5. Step 5: Solve for x
    x = 138.56/13.88
  6. Step 6: Final answer
    x = 9.98

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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.