Finding the Fourth Proportional to 111.42, 153.72 and 85.50

Step by Step Solution

1. Step 1: Write the proportion equation
   111.42 : 153.72 = 85.50 : x
2. Step 2: Convert to fraction form
   111.42/153.72 = 85.50/x
3. Step 3: Cross multiply
   111.42x = 153.72 × 85.50
4. Step 4: Simplify right side
   111.42x = 13,143.06
5. Step 5: Solve for x
   x = 13,143.06/111.42
6. Step 6: Final answer
   x = 117.96