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Finding the Third Proportional to 3,900 and 7,989

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Solution

The third proportional to 3,900 and 7,989 is: 16,365.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    3,900 : 7,989 = 7,989 : x
  2. Step 2: Convert to fraction form
    3,900/7,989 = 7,989/x
  3. Step 3: Cross multiply
    3,900x = 7,989 × 7,989
  4. Step 4: Simplify right side
    3,900x = 63,824,121
  5. Step 5: Solve for x
    x = 63,824,121/3,900
  6. Step 6: Final answer
    x = 16,365.16

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Why These Related Problems?

These problems maintain the same ratio (2.05) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.