Finding the Fourth Proportional to 111.72, 167.06 and 80.96

Step by Step Solution

1. Step 1: Write the proportion equation
   111.72 : 167.06 = 80.96 : x
2. Step 2: Convert to fraction form
   111.72/167.06 = 80.96/x
3. Step 3: Cross multiply
   111.72x = 167.06 × 80.96
4. Step 4: Simplify right side
   111.72x = 13,525.18
5. Step 5: Solve for x
   x = 13,525.18/111.72
6. Step 6: Final answer
   x = 121.06