Finding the Third Proportional to 396,555 and 638,365.50

Step by Step Solution

1. Step 1: Write the proportion equation
   396,555 : 638,365.50 = 638,365.50 : x
2. Step 2: Convert to fraction form
   396,555/638,365.50 = 638,365.50/x
3. Step 3: Cross multiply
   396,555x = 638,365.50 × 638,365.50
4. Step 4: Simplify right side
   396,555x = 407,510,511,590.25
5. Step 5: Solve for x
   x = 407,510,511,590.25/396,555
6. Step 6: Final answer
   x = 1,027,626.71