Finding the Third Proportional to 399,271 and 870,799

Step by Step Solution

1. Step 1: Write the proportion equation
   399,271 : 870,799 = 870,799 : x
2. Step 2: Convert to fraction form
   399,271/870,799 = 870,799/x
3. Step 3: Cross multiply
   399,271x = 870,799 × 870,799
4. Step 4: Simplify right side
   399,271x = 758,290,898,401
5. Step 5: Solve for x
   x = 758,290,898,401/399,271
6. Step 6: Final answer
   x = 1,899,188.52