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Finding the Fourth Proportional to 6.39, 8.78 and 6.31

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Solution

The fourth proportional to 6.39, 8.78 and 6.31 is: 8.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    6.39 : 8.78 = 6.31 : x
  2. Step 2: Convert to fraction form
    6.39/8.78 = 6.31/x
  3. Step 3: Cross multiply
    6.39x = 8.78 × 6.31
  4. Step 4: Simplify right side
    6.39x = 55.38
  5. Step 5: Solve for x
    x = 55.38/6.39
  6. Step 6: Final answer
    x = 8.67

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.