Finding the Third Proportional to 259,277 and 399,978

Step by Step Solution

1. Step 1: Write the proportion equation
   259,277 : 399,978 = 399,978 : x
2. Step 2: Convert to fraction form
   259,277/399,978 = 399,978/x
3. Step 3: Cross multiply
   259,277x = 399,978 × 399,978
4. Step 4: Simplify right side
   259,277x = 159,982,400,484
5. Step 5: Solve for x
   x = 159,982,400,484/259,277
6. Step 6: Final answer
   x = 617,032.75