Finding the Fourth Proportional to 111.72, 154.02 and 78.92

Step by Step Solution

1. Step 1: Write the proportion equation
   111.72 : 154.02 = 78.92 : x
2. Step 2: Convert to fraction form
   111.72/154.02 = 78.92/x
3. Step 3: Cross multiply
   111.72x = 154.02 × 78.92
4. Step 4: Simplify right side
   111.72x = 12,155.26
5. Step 5: Solve for x
   x = 12,155.26/111.72
6. Step 6: Final answer
   x = 108.80