Finding the Fourth Proportional to 105.20, 144.72 and 86.73

Step by Step Solution

1. Step 1: Write the proportion equation
   105.20 : 144.72 = 86.73 : x
2. Step 2: Convert to fraction form
   105.20/144.72 = 86.73/x
3. Step 3: Cross multiply
   105.20x = 144.72 × 86.73
4. Step 4: Simplify right side
   105.20x = 12,551.57
5. Step 5: Solve for x
   x = 12,551.57/105.20
6. Step 6: Final answer
   x = 119.32