Finding the Third Proportional to 381,978 and 809,490

Step by Step Solution

1. Step 1: Write the proportion equation
   381,978 : 809,490 = 809,490 : x
2. Step 2: Convert to fraction form
   381,978/809,490 = 809,490/x
3. Step 3: Cross multiply
   381,978x = 809,490 × 809,490
4. Step 4: Simplify right side
   381,978x = 655,274,060,100
5. Step 5: Solve for x
   x = 655,274,060,100/381,978
6. Step 6: Final answer
   x = 1,715,475.92