Finding the Third Proportional to 394,486 and 640,910.50

Step by Step Solution

1. Step 1: Write the proportion equation
   394,486 : 640,910.50 = 640,910.50 : x
2. Step 2: Convert to fraction form
   394,486/640,910.50 = 640,910.50/x
3. Step 3: Cross multiply
   394,486x = 640,910.50 × 640,910.50
4. Step 4: Simplify right side
   394,486x = 410,766,269,010.25
5. Step 5: Solve for x
   x = 410,766,269,010.25/394,486
6. Step 6: Final answer
   x = 1,041,269.57