Finding the Fourth Proportional to 111.06, 153.15 and 72.18

Step by Step Solution

1. Step 1: Write the proportion equation
   111.06 : 153.15 = 72.18 : x
2. Step 2: Convert to fraction form
   111.06/153.15 = 72.18/x
3. Step 3: Cross multiply
   111.06x = 153.15 × 72.18
4. Step 4: Simplify right side
   111.06x = 11,054.37
5. Step 5: Solve for x
   x = 11,054.37/111.06
6. Step 6: Final answer
   x = 99.54