Finding the Third Proportional to 399,616 and 856,090

Step by Step Solution

1. Step 1: Write the proportion equation
   399,616 : 856,090 = 856,090 : x
2. Step 2: Convert to fraction form
   399,616/856,090 = 856,090/x
3. Step 3: Cross multiply
   399,616x = 856,090 × 856,090
4. Step 4: Simplify right side
   399,616x = 732,890,088,100
5. Step 5: Solve for x
   x = 732,890,088,100/399,616
6. Step 6: Final answer
   x = 1,833,985.85