Finding the Third Proportional to 640,940 and 978,360

Step by Step Solution

1. Step 1: Write the proportion equation
   640,940 : 978,360 = 978,360 : x
2. Step 2: Convert to fraction form
   640,940/978,360 = 978,360/x
3. Step 3: Cross multiply
   640,940x = 978,360 × 978,360
4. Step 4: Simplify right side
   640,940x = 957,188,289,600
5. Step 5: Solve for x
   x = 957,188,289,600/640,940
6. Step 6: Final answer
   x = 1,493,413.25