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Finding the Fourth Proportional to 6.81, 9.40 and 6.31

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Solution

The fourth proportional to 6.81, 9.40 and 6.31 is: 8.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    6.81 : 9.40 = 6.31 : x
  2. Step 2: Convert to fraction form
    6.81/9.40 = 6.31/x
  3. Step 3: Cross multiply
    6.81x = 9.40 × 6.31
  4. Step 4: Simplify right side
    6.81x = 59.31
  5. Step 5: Solve for x
    x = 59.31/6.81
  6. Step 6: Final answer
    x = 8.71

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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.