Finding the Third Proportional to 685,903 and 978,409

Step by Step Solution

1. Step 1: Write the proportion equation
   685,903 : 978,409 = 978,409 : x
2. Step 2: Convert to fraction form
   685,903/978,409 = 978,409/x
3. Step 3: Cross multiply
   685,903x = 978,409 × 978,409
4. Step 4: Simplify right side
   685,903x = 957,284,171,281
5. Step 5: Solve for x
   x = 957,284,171,281/685,903
6. Step 6: Final answer
   x = 1,395,655.32