Finding the Third Proportional to 399,680 and 856,208

Step by Step Solution

1. Step 1: Write the proportion equation
   399,680 : 856,208 = 856,208 : x
2. Step 2: Convert to fraction form
   399,680/856,208 = 856,208/x
3. Step 3: Cross multiply
   399,680x = 856,208 × 856,208
4. Step 4: Simplify right side
   399,680x = 733,092,139,264
5. Step 5: Solve for x
   x = 733,092,139,264/399,680
6. Step 6: Final answer
   x = 1,834,197.71