Finding the Fourth Proportional to 111.48, 153.86 and 78.68

Step by Step Solution

1. Step 1: Write the proportion equation
   111.48 : 153.86 = 78.68 : x
2. Step 2: Convert to fraction form
   111.48/153.86 = 78.68/x
3. Step 3: Cross multiply
   111.48x = 153.86 × 78.68
4. Step 4: Simplify right side
   111.48x = 12,104.54
5. Step 5: Solve for x
   x = 12,104.54/111.48
6. Step 6: Final answer
   x = 108.58