Finding the Third Proportional to 321,907 and 509,611.50

Step by Step Solution

1. Step 1: Write the proportion equation
   321,907 : 509,611.50 = 509,611.50 : x
2. Step 2: Convert to fraction form
   321,907/509,611.50 = 509,611.50/x
3. Step 3: Cross multiply
   321,907x = 509,611.50 × 509,611.50
4. Step 4: Simplify right side
   321,907x = 259,703,880,932.25
5. Step 5: Solve for x
   x = 259,703,880,932.25/321,907
6. Step 6: Final answer
   x = 806,766.80