Finding the Fourth Proportional to 111.20, 153.40 and 69.72

Step by Step Solution

1. Step 1: Write the proportion equation
   111.20 : 153.40 = 69.72 : x
2. Step 2: Convert to fraction form
   111.20/153.40 = 69.72/x
3. Step 3: Cross multiply
   111.20x = 153.40 × 69.72
4. Step 4: Simplify right side
   111.20x = 10,695.05
5. Step 5: Solve for x
   x = 10,695.05/111.20
6. Step 6: Final answer
   x = 96.18