Finding the Fourth Proportional to 111.49, 153.78 and 78.24

Step by Step Solution

1. Step 1: Write the proportion equation
   111.49 : 153.78 = 78.24 : x
2. Step 2: Convert to fraction form
   111.49/153.78 = 78.24/x
3. Step 3: Cross multiply
   111.49x = 153.78 × 78.24
4. Step 4: Simplify right side
   111.49x = 12,031.75
5. Step 5: Solve for x
   x = 12,031.75/111.49
6. Step 6: Final answer
   x = 107.92