Finding the Third Proportional to 321,978 and 699,310.50

Step by Step Solution

1. Step 1: Write the proportion equation
   321,978 : 699,310.50 = 699,310.50 : x
2. Step 2: Convert to fraction form
   321,978/699,310.50 = 699,310.50/x
3. Step 3: Cross multiply
   321,978x = 699,310.50 × 699,310.50
4. Step 4: Simplify right side
   321,978x = 489,035,175,410.25
5. Step 5: Solve for x
   x = 489,035,175,410.25/321,978
6. Step 6: Final answer
   x = 1,518,846.55