Finding the Fourth Proportional to 105,139.83, 145,087.45 and 57,383.91

Step by Step Solution

1. Step 1: Write the proportion equation
   105,139.83 : 145,087.45 = 57,383.91 : x
2. Step 2: Convert to fraction form
   105,139.83/145,087.45 = 57,383.91/x
3. Step 3: Cross multiply
   105,139.83x = 145,087.45 × 57,383.91
4. Step 4: Simplify right side
   105,139.83x = 8,325,685,172.93
5. Step 5: Solve for x
   x = 8,325,685,172.93/105,139.83
6. Step 6: Final answer
   x = 79,186.79