Finding the Fourth Proportional to 111.12, 153.42 and 109.20

Step by Step Solution

1. Step 1: Write the proportion equation
   111.12 : 153.42 = 109.20 : x
2. Step 2: Convert to fraction form
   111.12/153.42 = 109.20/x
3. Step 3: Cross multiply
   111.12x = 153.42 × 109.20
4. Step 4: Simplify right side
   111.12x = 16,753.46
5. Step 5: Solve for x
   x = 16,753.46/111.12
6. Step 6: Final answer
   x = 150.77