Finding the Fourth Proportional to 111.91, 168.84 and 111.61

Step by Step Solution

1. Step 1: Write the proportion equation
   111.91 : 168.84 = 111.61 : x
2. Step 2: Convert to fraction form
   111.91/168.84 = 111.61/x
3. Step 3: Cross multiply
   111.91x = 168.84 × 111.61
4. Step 4: Simplify right side
   111.91x = 18,844.23
5. Step 5: Solve for x
   x = 18,844.23/111.91
6. Step 6: Final answer
   x = 168.39