Finding the Third Proportional to 399,116 and 631,870

Step by Step Solution

1. Step 1: Write the proportion equation
   399,116 : 631,870 = 631,870 : x
2. Step 2: Convert to fraction form
   399,116/631,870 = 631,870/x
3. Step 3: Cross multiply
   399,116x = 631,870 × 631,870
4. Step 4: Simplify right side
   399,116x = 399,259,696,900
5. Step 5: Solve for x
   x = 399,259,696,900/399,116
6. Step 6: Final answer
   x = 1,000,360.04