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Finding the Fourth Proportional to 13.18, 19.81 and 6.43

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Solution

The fourth proportional to 13.18, 19.81 and 6.43 is: 9.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    13.18 : 19.81 = 6.43 : x
  2. Step 2: Convert to fraction form
    13.18/19.81 = 6.43/x
  3. Step 3: Cross multiply
    13.18x = 19.81 × 6.43
  4. Step 4: Simplify right side
    13.18x = 127.28
  5. Step 5: Solve for x
    x = 127.28/13.18
  6. Step 6: Final answer
    x = 9.66

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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.