Finding the Fourth Proportional to 111.48, 153.81 and 78.81

Step by Step Solution

1. Step 1: Write the proportion equation
   111.48 : 153.81 = 78.81 : x
2. Step 2: Convert to fraction form
   111.48/153.81 = 78.81/x
3. Step 3: Cross multiply
   111.48x = 153.81 × 78.81
4. Step 4: Simplify right side
   111.48x = 12,121.77
5. Step 5: Solve for x
   x = 12,121.77/111.48
6. Step 6: Final answer
   x = 108.73