Finding the Fourth Proportional to 111.25, 166.61 and 91.96

Step by Step Solution

1. Step 1: Write the proportion equation
   111.25 : 166.61 = 91.96 : x
2. Step 2: Convert to fraction form
   111.25/166.61 = 91.96/x
3. Step 3: Cross multiply
   111.25x = 166.61 × 91.96
4. Step 4: Simplify right side
   111.25x = 15,321.22
5. Step 5: Solve for x
   x = 15,321.22/111.25
6. Step 6: Final answer
   x = 137.72