Finding the Third Proportional to 333,990 and 679,639.50

Step by Step Solution

1. Step 1: Write the proportion equation
   333,990 : 679,639.50 = 679,639.50 : x
2. Step 2: Convert to fraction form
   333,990/679,639.50 = 679,639.50/x
3. Step 3: Cross multiply
   333,990x = 679,639.50 × 679,639.50
4. Step 4: Simplify right side
   333,990x = 461,909,849,960.25
5. Step 5: Solve for x
   x = 461,909,849,960.25/333,990
6. Step 6: Final answer
   x = 1,383,005.03