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Finding the Fourth Proportional to 12.81, 17.67 and 8.21

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Solution

The fourth proportional to 12.81, 17.67 and 8.21 is: 11.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.81 : 17.67 = 8.21 : x
  2. Step 2: Convert to fraction form
    12.81/17.67 = 8.21/x
  3. Step 3: Cross multiply
    12.81x = 17.67 × 8.21
  4. Step 4: Simplify right side
    12.81x = 145.00
  5. Step 5: Solve for x
    x = 145.00/12.81
  6. Step 6: Final answer
    x = 11.32

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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.