Finding the Third Proportional to 685,899 and 978,403.50

Step by Step Solution

1. Step 1: Write the proportion equation
   685,899 : 978,403.50 = 978,403.50 : x
2. Step 2: Convert to fraction form
   685,899/978,403.50 = 978,403.50/x
3. Step 3: Cross multiply
   685,899x = 978,403.50 × 978,403.50
4. Step 4: Simplify right side
   685,899x = 957,273,408,812.25
5. Step 5: Solve for x
   x = 957,273,408,812.25/685,899
6. Step 6: Final answer
   x = 1,395,647.77