Finding the Fourth Proportional to 111.50, 153.82 and 78.80

Step by Step Solution

1. Step 1: Write the proportion equation
   111.50 : 153.82 = 78.80 : x
2. Step 2: Convert to fraction form
   111.50/153.82 = 78.80/x
3. Step 3: Cross multiply
   111.50x = 153.82 × 78.80
4. Step 4: Simplify right side
   111.50x = 12,121.02
5. Step 5: Solve for x
   x = 12,121.02/111.50
6. Step 6: Final answer
   x = 108.71