Finding the Third Proportional to 405,828 and 642,583.50

Step by Step Solution

1. Step 1: Write the proportion equation
   405,828 : 642,583.50 = 642,583.50 : x
2. Step 2: Convert to fraction form
   405,828/642,583.50 = 642,583.50/x
3. Step 3: Cross multiply
   405,828x = 642,583.50 × 642,583.50
4. Step 4: Simplify right side
   405,828x = 412,913,554,472.25
5. Step 5: Solve for x
   x = 412,913,554,472.25/405,828
6. Step 6: Final answer
   x = 1,017,459.50