Finding the Fourth Proportional to 111.53, 153.72 and 88.17

Step by Step Solution

1. Step 1: Write the proportion equation
   111.53 : 153.72 = 88.17 : x
2. Step 2: Convert to fraction form
   111.53/153.72 = 88.17/x
3. Step 3: Cross multiply
   111.53x = 153.72 × 88.17
4. Step 4: Simplify right side
   111.53x = 13,553.71
5. Step 5: Solve for x
   x = 13,553.71/111.53
6. Step 6: Final answer
   x = 121.53