Finding the Fourth Proportional to 111.10, 166.58 and 67.78

Step by Step Solution

1. Step 1: Write the proportion equation
   111.10 : 166.58 = 67.78 : x
2. Step 2: Convert to fraction form
   111.10/166.58 = 67.78/x
3. Step 3: Cross multiply
   111.10x = 166.58 × 67.78
4. Step 4: Simplify right side
   111.10x = 11,290.79
5. Step 5: Solve for x
   x = 11,290.79/111.10
6. Step 6: Final answer
   x = 101.63