Finding the Fourth Proportional to 111.42, 153.81 and 83.88

Step by Step Solution

1. Step 1: Write the proportion equation
   111.42 : 153.81 = 83.88 : x
2. Step 2: Convert to fraction form
   111.42/153.81 = 83.88/x
3. Step 3: Cross multiply
   111.42x = 153.81 × 83.88
4. Step 4: Simplify right side
   111.42x = 12,901.58
5. Step 5: Solve for x
   x = 12,901.58/111.42
6. Step 6: Final answer
   x = 115.79