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Finding the Fourth Proportional to 6.87, 10.31 and 3.86

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Solution

The fourth proportional to 6.87, 10.31 and 3.86 is: 5.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    6.87 : 10.31 = 3.86 : x
  2. Step 2: Convert to fraction form
    6.87/10.31 = 3.86/x
  3. Step 3: Cross multiply
    6.87x = 10.31 × 3.86
  4. Step 4: Simplify right side
    6.87x = 39.73
  5. Step 5: Solve for x
    x = 39.73/6.87
  6. Step 6: Final answer
    x = 5.78

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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.