Finding the Fourth Proportional to 112.89, 168.18 and 105.91

Step by Step Solution

1. Step 1: Write the proportion equation
   112.89 : 168.18 = 105.91 : x
2. Step 2: Convert to fraction form
   112.89/168.18 = 105.91/x
3. Step 3: Cross multiply
   112.89x = 168.18 × 105.91
4. Step 4: Simplify right side
   112.89x = 17,811.94
5. Step 5: Solve for x
   x = 17,811.94/112.89
6. Step 6: Final answer
   x = 157.78