Finding the Fourth Proportional to 111.96, 168.18 and 111.78

Step by Step Solution

1. Step 1: Write the proportion equation
   111.96 : 168.18 = 111.78 : x
2. Step 2: Convert to fraction form
   111.96/168.18 = 111.78/x
3. Step 3: Cross multiply
   111.96x = 168.18 × 111.78
4. Step 4: Simplify right side
   111.96x = 18,799.16
5. Step 5: Solve for x
   x = 18,799.16/111.96
6. Step 6: Final answer
   x = 167.91