Finding the Fourth Proportional to 111.69, 154.06 and 89.91

Step by Step Solution

1. Step 1: Write the proportion equation
   111.69 : 154.06 = 89.91 : x
2. Step 2: Convert to fraction form
   111.69/154.06 = 89.91/x
3. Step 3: Cross multiply
   111.69x = 154.06 × 89.91
4. Step 4: Simplify right side
   111.69x = 13,851.53
5. Step 5: Solve for x
   x = 13,851.53/111.69
6. Step 6: Final answer
   x = 124.02