Finding the Fourth Proportional to 105.46, 158.79 and 78.60

Step by Step Solution

1. Step 1: Write the proportion equation
   105.46 : 158.79 = 78.60 : x
2. Step 2: Convert to fraction form
   105.46/158.79 = 78.60/x
3. Step 3: Cross multiply
   105.46x = 158.79 × 78.60
4. Step 4: Simplify right side
   105.46x = 12,480.89
5. Step 5: Solve for x
   x = 12,480.89/105.46
6. Step 6: Final answer
   x = 118.35