Finding the Third Proportional to 3,945,678 and 8,621,916

Step by Step Solution

1. Step 1: Write the proportion equation
   3,945,678 : 8,621,916 = 8,621,916 : x
2. Step 2: Convert to fraction form
   3,945,678/8,621,916 = 8,621,916/x
3. Step 3: Cross multiply
   3,945,678x = 8,621,916 × 8,621,916
4. Step 4: Simplify right side
   3,945,678x = 74,337,435,511,056
5. Step 5: Solve for x
   x = 74,337,435,511,056/3,945,678
6. Step 6: Final answer
   x = 18,840,218.46