Finding the Fourth Proportional to 111.56, 153.78 and 109.40

Step by Step Solution

1. Step 1: Write the proportion equation
   111.56 : 153.78 = 109.40 : x
2. Step 2: Convert to fraction form
   111.56/153.78 = 109.40/x
3. Step 3: Cross multiply
   111.56x = 153.78 × 109.40
4. Step 4: Simplify right side
   111.56x = 16,823.53
5. Step 5: Solve for x
   x = 16,823.53/111.56
6. Step 6: Final answer
   x = 150.80