Finding the Fourth Proportional to 111.91, 154.32 and 80.76

Step by Step Solution

1. Step 1: Write the proportion equation
   111.91 : 154.32 = 80.76 : x
2. Step 2: Convert to fraction form
   111.91/154.32 = 80.76/x
3. Step 3: Cross multiply
   111.91x = 154.32 × 80.76
4. Step 4: Simplify right side
   111.91x = 12,462.88
5. Step 5: Solve for x
   x = 12,462.88/111.91
6. Step 6: Final answer
   x = 111.37