Finding the Third Proportional to 3,940,478 and 8,509,660

Step by Step Solution

1. Step 1: Write the proportion equation
   3,940,478 : 8,509,660 = 8,509,660 : x
2. Step 2: Convert to fraction form
   3,940,478/8,509,660 = 8,509,660/x
3. Step 3: Cross multiply
   3,940,478x = 8,509,660 × 8,509,660
4. Step 4: Simplify right side
   3,940,478x = 72,414,313,315,600
5. Step 5: Solve for x
   x = 72,414,313,315,600/3,940,478
6. Step 6: Final answer
   x = 18,377,037.84