Finding the Third Proportional to 156,978 and 322,218

Step by Step Solution

1. Step 1: Write the proportion equation
   156,978 : 322,218 = 322,218 : x
2. Step 2: Convert to fraction form
   156,978/322,218 = 322,218/x
3. Step 3: Cross multiply
   156,978x = 322,218 × 322,218
4. Step 4: Simplify right side
   156,978x = 103,824,439,524
5. Step 5: Solve for x
   x = 103,824,439,524/156,978
6. Step 6: Final answer
   x = 661,394.84