Finding the Fourth Proportional to 111.46, 153.78 and 72.12

Step by Step Solution

1. Step 1: Write the proportion equation
   111.46 : 153.78 = 72.12 : x
2. Step 2: Convert to fraction form
   111.46/153.78 = 72.12/x
3. Step 3: Cross multiply
   111.46x = 153.78 × 72.12
4. Step 4: Simplify right side
   111.46x = 11,091.10
5. Step 5: Solve for x
   x = 11,091.10/111.46
6. Step 6: Final answer
   x = 99.51