Finding the Third Proportional to 399,290 and 856,996

Step by Step Solution

1. Step 1: Write the proportion equation
   399,290 : 856,996 = 856,996 : x
2. Step 2: Convert to fraction form
   399,290/856,996 = 856,996/x
3. Step 3: Cross multiply
   399,290x = 856,996 × 856,996
4. Step 4: Simplify right side
   399,290x = 734,442,144,016
5. Step 5: Solve for x
   x = 734,442,144,016/399,290
6. Step 6: Final answer
   x = 1,839,370.24