Finding the Fourth Proportional to 105,815.03, 158,662.40 and 81,790.83

Step by Step Solution

1. Step 1: Write the proportion equation
   105,815.03 : 158,662.40 = 81,790.83 : x
2. Step 2: Convert to fraction form
   105,815.03/158,662.40 = 81,790.83/x
3. Step 3: Cross multiply
   105,815.03x = 158,662.40 × 81,790.83
4. Step 4: Simplify right side
   105,815.03x = 12,977,128,976.84
5. Step 5: Solve for x
   x = 12,977,128,976.84/105,815.03
6. Step 6: Final answer
   x = 122,639.76