Finding the Fourth Proportional to 111.18, 166.56 and 76.86

Step by Step Solution

1. Step 1: Write the proportion equation
   111.18 : 166.56 = 76.86 : x
2. Step 2: Convert to fraction form
   111.18/166.56 = 76.86/x
3. Step 3: Cross multiply
   111.18x = 166.56 × 76.86
4. Step 4: Simplify right side
   111.18x = 12,801.80
5. Step 5: Solve for x
   x = 12,801.80/111.18
6. Step 6: Final answer
   x = 115.14