Finding the Fourth Proportional to 111.06, 166.37 and 86.37

Step by Step Solution

1. Step 1: Write the proportion equation
   111.06 : 166.37 = 86.37 : x
2. Step 2: Convert to fraction form
   111.06/166.37 = 86.37/x
3. Step 3: Cross multiply
   111.06x = 166.37 × 86.37
4. Step 4: Simplify right side
   111.06x = 14,369.27
5. Step 5: Solve for x
   x = 14,369.27/111.06
6. Step 6: Final answer
   x = 129.38