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Finding the Fourth Proportional to 13.67, 18.86 and 8.21

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Solution

The fourth proportional to 13.67, 18.86 and 8.21 is: 11.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.67 : 18.86 = 8.21 : x
  2. Step 2: Convert to fraction form
    13.67/18.86 = 8.21/x
  3. Step 3: Cross multiply
    13.67x = 18.86 × 8.21
  4. Step 4: Simplify right side
    13.67x = 154.84
  5. Step 5: Solve for x
    x = 154.84/13.67
  6. Step 6: Final answer
    x = 11.33

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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.