Finding the Third Proportional to 309,722 and 685,770

Step by Step Solution

1. Step 1: Write the proportion equation
   309,722 : 685,770 = 685,770 : x
2. Step 2: Convert to fraction form
   309,722/685,770 = 685,770/x
3. Step 3: Cross multiply
   309,722x = 685,770 × 685,770
4. Step 4: Simplify right side
   309,722x = 470,280,492,900
5. Step 5: Solve for x
   x = 470,280,492,900/309,722
6. Step 6: Final answer
   x = 1,518,395.51