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Finding the Fourth Proportional to 13.71, 18.91 and 9.11

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Solution

The fourth proportional to 13.71, 18.91 and 9.11 is: 12.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.71 : 18.91 = 9.11 : x
  2. Step 2: Convert to fraction form
    13.71/18.91 = 9.11/x
  3. Step 3: Cross multiply
    13.71x = 18.91 × 9.11
  4. Step 4: Simplify right side
    13.71x = 172.13
  5. Step 5: Solve for x
    x = 172.13/13.71
  6. Step 6: Final answer
    x = 12.56

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.