Finding the Fourth Proportional to 111.05, 153.11 and 91.31

Step by Step Solution

1. Step 1: Write the proportion equation
   111.05 : 153.11 = 91.31 : x
2. Step 2: Convert to fraction form
   111.05/153.11 = 91.31/x
3. Step 3: Cross multiply
   111.05x = 153.11 × 91.31
4. Step 4: Simplify right side
   111.05x = 13,980.47
5. Step 5: Solve for x
   x = 13,980.47/111.05
6. Step 6: Final answer
   x = 125.89