Finding the Fourth Proportional to 90.27, 134.76 and 86.33

Step by Step Solution

1. Step 1: Write the proportion equation
   90.27 : 134.76 = 86.33 : x
2. Step 2: Convert to fraction form
   90.27/134.76 = 86.33/x
3. Step 3: Cross multiply
   90.27x = 134.76 × 86.33
4. Step 4: Simplify right side
   90.27x = 11,633.83
5. Step 5: Solve for x
   x = 11,633.83/90.27
6. Step 6: Final answer
   x = 128.88