Finding the Fourth Proportional to 111.12, 153.50 and 100.77

Step by Step Solution

1. Step 1: Write the proportion equation
   111.12 : 153.50 = 100.77 : x
2. Step 2: Convert to fraction form
   111.12/153.50 = 100.77/x
3. Step 3: Cross multiply
   111.12x = 153.50 × 100.77
4. Step 4: Simplify right side
   111.12x = 15,467.69
5. Step 5: Solve for x
   x = 15,467.69/111.12
6. Step 6: Final answer
   x = 139.20