Finding the Fourth Proportional to 111.89, 154.43 and 80.43

Step by Step Solution

1. Step 1: Write the proportion equation
   111.89 : 154.43 = 80.43 : x
2. Step 2: Convert to fraction form
   111.89/154.43 = 80.43/x
3. Step 3: Cross multiply
   111.89x = 154.43 × 80.43
4. Step 4: Simplify right side
   111.89x = 12,420.13
5. Step 5: Solve for x
   x = 12,420.13/111.89
6. Step 6: Final answer
   x = 111.00