Finding the Third Proportional to 428,826 and 647,607

Step by Step Solution

1. Step 1: Write the proportion equation
   428,826 : 647,607 = 647,607 : x
2. Step 2: Convert to fraction form
   428,826/647,607 = 647,607/x
3. Step 3: Cross multiply
   428,826x = 647,607 × 647,607
4. Step 4: Simplify right side
   428,826x = 419,394,826,449
5. Step 5: Solve for x
   x = 419,394,826,449/428,826
6. Step 6: Final answer
   x = 978,006.99