Finding the Third Proportional to 309,710.25 and 685,749.38

Step by Step Solution

1. Step 1: Write the proportion equation
   309,710.25 : 685,749.38 = 685,749.38 : x
2. Step 2: Convert to fraction form
   309,710.25/685,749.38 = 685,749.38/x
3. Step 3: Cross multiply
   309,710.25x = 685,749.38 × 685,749.38
4. Step 4: Simplify right side
   309,710.25x = 470,252,205,312.89
5. Step 5: Solve for x
   x = 470,252,205,312.89/309,710.25
6. Step 6: Final answer
   x = 1,518,361.78