Finding the Third Proportional to 404,991 and 643,657

Step by Step Solution

1. Step 1: Write the proportion equation
   404,991 : 643,657 = 643,657 : x
2. Step 2: Convert to fraction form
   404,991/643,657 = 643,657/x
3. Step 3: Cross multiply
   404,991x = 643,657 × 643,657
4. Step 4: Simplify right side
   404,991x = 414,294,333,649
5. Step 5: Solve for x
   x = 414,294,333,649/404,991
6. Step 6: Final answer
   x = 1,022,971.70