Finding the Fourth Proportional to 399,978.41, 552,338.49 and 256,987.59

Step by Step Solution

1. Step 1: Write the proportion equation
   399,978.41 : 552,338.49 = 256,987.59 : x
2. Step 2: Convert to fraction form
   399,978.41/552,338.49 = 256,987.59/x
3. Step 3: Cross multiply
   399,978.41x = 552,338.49 × 256,987.59
4. Step 4: Simplify right side
   399,978.41x = 141,944,136,301.77
5. Step 5: Solve for x
   x = 141,944,136,301.77/399,978.41
6. Step 6: Final answer
   x = 354,879.50