Finding the Third Proportional to 396,406 and 612,105

Step by Step Solution

1. Step 1: Write the proportion equation
   396,406 : 612,105 = 612,105 : x
2. Step 2: Convert to fraction form
   396,406/612,105 = 612,105/x
3. Step 3: Cross multiply
   396,406x = 612,105 × 612,105
4. Step 4: Simplify right side
   396,406x = 374,672,531,025
5. Step 5: Solve for x
   x = 374,672,531,025/396,406
6. Step 6: Final answer
   x = 945,173.71