Finding the Third Proportional to 399,055.50 and 816,754.50

Step by Step Solution

1. Step 1: Write the proportion equation
   399,055.50 : 816,754.50 = 816,754.50 : x
2. Step 2: Convert to fraction form
   399,055.50/816,754.50 = 816,754.50/x
3. Step 3: Cross multiply
   399,055.50x = 816,754.50 × 816,754.50
4. Step 4: Simplify right side
   399,055.50x = 667,087,913,270.25
5. Step 5: Solve for x
   x = 667,087,913,270.25/399,055.50
6. Step 6: Final answer
   x = 1,671,667.01