Finding the Fourth Proportional to 111.36, 153.83 and 89.61

Step by Step Solution

1. Step 1: Write the proportion equation
   111.36 : 153.83 = 89.61 : x
2. Step 2: Convert to fraction form
   111.36/153.83 = 89.61/x
3. Step 3: Cross multiply
   111.36x = 153.83 × 89.61
4. Step 4: Simplify right side
   111.36x = 13,784.26
5. Step 5: Solve for x
   x = 13,784.26/111.36
6. Step 6: Final answer
   x = 123.78