Finding the Fourth Proportional to 105,537.30, 158,075.55 and 81,978.90

Step by Step Solution

1. Step 1: Write the proportion equation
   105,537.30 : 158,075.55 = 81,978.90 : x
2. Step 2: Convert to fraction form
   105,537.30/158,075.55 = 81,978.90/x
3. Step 3: Cross multiply
   105,537.30x = 158,075.55 × 81,978.90
4. Step 4: Simplify right side
   105,537.30x = 12,958,859,705.90
5. Step 5: Solve for x
   x = 12,958,859,705.90/105,537.30
6. Step 6: Final answer
   x = 122,789.38