Finding the Fourth Proportional to 111.89, 168.60 and 105.05

Step by Step Solution

1. Step 1: Write the proportion equation
   111.89 : 168.60 = 105.05 : x
2. Step 2: Convert to fraction form
   111.89/168.60 = 105.05/x
3. Step 3: Cross multiply
   111.89x = 168.60 × 105.05
4. Step 4: Simplify right side
   111.89x = 17,710.59
5. Step 5: Solve for x
   x = 17,710.59/111.89
6. Step 6: Final answer
   x = 158.29