Finding the Fourth Proportional to 111.31, 153.70 and 88.09

Step by Step Solution

1. Step 1: Write the proportion equation
   111.31 : 153.70 = 88.09 : x
2. Step 2: Convert to fraction form
   111.31/153.70 = 88.09/x
3. Step 3: Cross multiply
   111.31x = 153.70 × 88.09
4. Step 4: Simplify right side
   111.31x = 13,538.83
5. Step 5: Solve for x
   x = 13,538.83/111.31
6. Step 6: Final answer
   x = 121.63