Finding the Fourth Proportional to 90.42, 124.83 and 86.55

Step by Step Solution

1. Step 1: Write the proportion equation
   90.42 : 124.83 = 86.55 : x
2. Step 2: Convert to fraction form
   90.42/124.83 = 86.55/x
3. Step 3: Cross multiply
   90.42x = 124.83 × 86.55
4. Step 4: Simplify right side
   90.42x = 10,804.04
5. Step 5: Solve for x
   x = 10,804.04/90.42
6. Step 6: Final answer
   x = 119.49