Finding the Fourth Proportional to 108.42, 149.83 and 86.55

Step by Step Solution

1. Step 1: Write the proportion equation
   108.42 : 149.83 = 86.55 : x
2. Step 2: Convert to fraction form
   108.42/149.83 = 86.55/x
3. Step 3: Cross multiply
   108.42x = 149.83 × 86.55
4. Step 4: Simplify right side
   108.42x = 12,967.50
5. Step 5: Solve for x
   x = 12,967.50/108.42
6. Step 6: Final answer
   x = 119.61