Finding the Fourth Proportional to 258,858.86, 388,381.70 and 90,404.10

Step by Step Solution

1. Step 1: Write the proportion equation
   258,858.86 : 388,381.70 = 90,404.10 : x
2. Step 2: Convert to fraction form
   258,858.86/388,381.70 = 90,404.10/x
3. Step 3: Cross multiply
   258,858.86x = 388,381.70 × 90,404.10
4. Step 4: Simplify right side
   258,858.86x = 35,111,298,270.98
5. Step 5: Solve for x
   x = 35,111,298,270.98/258,858.86
6. Step 6: Final answer
   x = 135,638.78