Finding the Fourth Proportional to 111.37, 153.46 and 86.80

Step by Step Solution

1. Step 1: Write the proportion equation
   111.37 : 153.46 = 86.80 : x
2. Step 2: Convert to fraction form
   111.37/153.46 = 86.80/x
3. Step 3: Cross multiply
   111.37x = 153.46 × 86.80
4. Step 4: Simplify right side
   111.37x = 13,320.33
5. Step 5: Solve for x
   x = 13,320.33/111.37
6. Step 6: Final answer
   x = 119.60