Finding the Fourth Proportional to 111.20, 153.42 and 72.41

Step by Step Solution

1. Step 1: Write the proportion equation
   111.20 : 153.42 = 72.41 : x
2. Step 2: Convert to fraction form
   111.20/153.42 = 72.41/x
3. Step 3: Cross multiply
   111.20x = 153.42 × 72.41
4. Step 4: Simplify right side
   111.20x = 11,109.14
5. Step 5: Solve for x
   x = 11,109.14/111.20
6. Step 6: Final answer
   x = 99.90