Finding the Fourth Proportional to 105.69, 158.24 and 78.09

Step by Step Solution

1. Step 1: Write the proportion equation
   105.69 : 158.24 = 78.09 : x
2. Step 2: Convert to fraction form
   105.69/158.24 = 78.09/x
3. Step 3: Cross multiply
   105.69x = 158.24 × 78.09
4. Step 4: Simplify right side
   105.69x = 12,355.90
5. Step 5: Solve for x
   x = 12,355.90/105.69
6. Step 6: Final answer
   x = 116.90