Finding the Fourth Proportional to 111.67, 153.96 and 80.56

Step by Step Solution

1. Step 1: Write the proportion equation
   111.67 : 153.96 = 80.56 : x
2. Step 2: Convert to fraction form
   111.67/153.96 = 80.56/x
3. Step 3: Cross multiply
   111.67x = 153.96 × 80.56
4. Step 4: Simplify right side
   111.67x = 12,403.02
5. Step 5: Solve for x
   x = 12,403.02/111.67
6. Step 6: Final answer
   x = 111.07