Finding the Third Proportional to 685,905 and 978,412

Step by Step Solution

1. Step 1: Write the proportion equation
   685,905 : 978,412 = 978,412 : x
2. Step 2: Convert to fraction form
   685,905/978,412 = 978,412/x
3. Step 3: Cross multiply
   685,905x = 978,412 × 978,412
4. Step 4: Simplify right side
   685,905x = 957,290,041,744
5. Step 5: Solve for x
   x = 957,290,041,744/685,905
6. Step 6: Final answer
   x = 1,395,659.81