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Finding the Fourth Proportional to 8.20, 12.30 and 6.86

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Solution

The fourth proportional to 8.20, 12.30 and 6.86 is: 10.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.20 : 12.30 = 6.86 : x
  2. Step 2: Convert to fraction form
    8.20/12.30 = 6.86/x
  3. Step 3: Cross multiply
    8.20x = 12.30 × 6.86
  4. Step 4: Simplify right side
    8.20x = 84.38
  5. Step 5: Solve for x
    x = 84.38/8.20
  6. Step 6: Final answer
    x = 10.29

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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.