Finding the Fourth Proportional to 111.18, 153 and 89.99

Step by Step Solution

1. Step 1: Write the proportion equation
   111.18 : 153 = 89.99 : x
2. Step 2: Convert to fraction form
   111.18/153 = 89.99/x
3. Step 3: Cross multiply
   111.18x = 153 × 89.99
4. Step 4: Simplify right side
   111.18x = 13,768.47
5. Step 5: Solve for x
   x = 13,768.47/111.18
6. Step 6: Final answer
   x = 123.84