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Finding the Third Proportional to 3,978 and 8,639

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Solution

The third proportional to 3,978 and 8,639 is: 18,761.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,978 : 8,639 = 8,639 : x
  2. Step 2: Convert to fraction form
    3,978/8,639 = 8,639/x
  3. Step 3: Cross multiply
    3,978x = 8,639 × 8,639
  4. Step 4: Simplify right side
    3,978x = 74,632,321
  5. Step 5: Solve for x
    x = 74,632,321/3,978
  6. Step 6: Final answer
    x = 18,761.27

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Why These Related Problems?

These problems maintain the same ratio (2.17) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.