Finding the Fourth Proportional to 111.60, 154.05 and 78.96

Step by Step Solution

1. Step 1: Write the proportion equation
   111.60 : 154.05 = 78.96 : x
2. Step 2: Convert to fraction form
   111.60/154.05 = 78.96/x
3. Step 3: Cross multiply
   111.60x = 154.05 × 78.96
4. Step 4: Simplify right side
   111.60x = 12,163.79
5. Step 5: Solve for x
   x = 12,163.79/111.60
6. Step 6: Final answer
   x = 108.99