Finding the Fourth Proportional to 111.54, 153.78 and 108.42

Step by Step Solution

1. Step 1: Write the proportion equation
   111.54 : 153.78 = 108.42 : x
2. Step 2: Convert to fraction form
   111.54/153.78 = 108.42/x
3. Step 3: Cross multiply
   111.54x = 153.78 × 108.42
4. Step 4: Simplify right side
   111.54x = 16,672.83
5. Step 5: Solve for x
   x = 16,672.83/111.54
6. Step 6: Final answer
   x = 149.48