Finding the Fourth Proportional to 111.53, 153.86 and 72.18

Step by Step Solution

1. Step 1: Write the proportion equation
   111.53 : 153.86 = 72.18 : x
2. Step 2: Convert to fraction form
   111.53/153.86 = 72.18/x
3. Step 3: Cross multiply
   111.53x = 153.86 × 72.18
4. Step 4: Simplify right side
   111.53x = 11,105.61
5. Step 5: Solve for x
   x = 11,105.61/111.53
6. Step 6: Final answer
   x = 99.58