Finding the Third Proportional to 685,923 and 978,439

Step by Step Solution

1. Step 1: Write the proportion equation
   685,923 : 978,439 = 978,439 : x
2. Step 2: Convert to fraction form
   685,923/978,439 = 978,439/x
3. Step 3: Cross multiply
   685,923x = 978,439 × 978,439
4. Step 4: Simplify right side
   685,923x = 957,342,876,721
5. Step 5: Solve for x
   x = 957,342,876,721/685,923
6. Step 6: Final answer
   x = 1,395,700.21