Finding the Fourth Proportional to 111.72, 154.18 and 72.88

Step by Step Solution

1. Step 1: Write the proportion equation
   111.72 : 154.18 = 72.88 : x
2. Step 2: Convert to fraction form
   111.72/154.18 = 72.88/x
3. Step 3: Cross multiply
   111.72x = 154.18 × 72.88
4. Step 4: Simplify right side
   111.72x = 11,236.64
5. Step 5: Solve for x
   x = 11,236.64/111.72
6. Step 6: Final answer
   x = 100.58