Finding the Third Proportional to 399,012 and 853,308

Step by Step Solution

1. Step 1: Write the proportion equation
   399,012 : 853,308 = 853,308 : x
2. Step 2: Convert to fraction form
   399,012/853,308 = 853,308/x
3. Step 3: Cross multiply
   399,012x = 853,308 × 853,308
4. Step 4: Simplify right side
   399,012x = 728,134,542,864
5. Step 5: Solve for x
   x = 728,134,542,864/399,012
6. Step 6: Final answer
   x = 1,824,843.72