Finding the Fourth Proportional to 419,172.32, 578,286.88 and 257,978.72

Step by Step Solution

1. Step 1: Write the proportion equation
   419,172.32 : 578,286.88 = 257,978.72 : x
2. Step 2: Convert to fraction form
   419,172.32/578,286.88 = 257,978.72/x
3. Step 3: Cross multiply
   419,172.32x = 578,286.88 × 257,978.72
4. Step 4: Simplify right side
   419,172.32x = 149,185,709,095.19
5. Step 5: Solve for x
   x = 149,185,709,095.19/419,172.32
6. Step 6: Final answer
   x = 355,905.44