Finding the Fourth Proportional to 111.35, 153.55 and 78.54

Step by Step Solution

1. Step 1: Write the proportion equation
   111.35 : 153.55 = 78.54 : x
2. Step 2: Convert to fraction form
   111.35/153.55 = 78.54/x
3. Step 3: Cross multiply
   111.35x = 153.55 × 78.54
4. Step 4: Simplify right side
   111.35x = 12,059.82
5. Step 5: Solve for x
   x = 12,059.82/111.35
6. Step 6: Final answer
   x = 108.31