Finding the Fourth Proportional to 111.42, 166.20 and 108

Step by Step Solution

1. Step 1: Write the proportion equation
   111.42 : 166.20 = 108 : x
2. Step 2: Convert to fraction form
   111.42/166.20 = 108/x
3. Step 3: Cross multiply
   111.42x = 166.20 × 108
4. Step 4: Simplify right side
   111.42x = 17,949.60
5. Step 5: Solve for x
   x = 17,949.60/111.42
6. Step 6: Final answer
   x = 161.10