Finding the Third Proportional to 321,912 and 685,404

Step by Step Solution

1. Step 1: Write the proportion equation
   321,912 : 685,404 = 685,404 : x
2. Step 2: Convert to fraction form
   321,912/685,404 = 685,404/x
3. Step 3: Cross multiply
   321,912x = 685,404 × 685,404
4. Step 4: Simplify right side
   321,912x = 469,778,643,216
5. Step 5: Solve for x
   x = 469,778,643,216/321,912
6. Step 6: Final answer
   x = 1,459,338.71