Finding the Fourth Proportional to 111.47, 153.77 and 90.77

Step by Step Solution

1. Step 1: Write the proportion equation
   111.47 : 153.77 = 90.77 : x
2. Step 2: Convert to fraction form
   111.47/153.77 = 90.77/x
3. Step 3: Cross multiply
   111.47x = 153.77 × 90.77
4. Step 4: Simplify right side
   111.47x = 13,956.48
5. Step 5: Solve for x
   x = 13,956.48/111.47
6. Step 6: Final answer
   x = 125.21