Finding the Fourth Proportional to 233.21, 321.83 and 128.31

Step by Step Solution

1. Step 1: Write the proportion equation
   233.21 : 321.83 = 128.31 : x
2. Step 2: Convert to fraction form
   233.21/321.83 = 128.31/x
3. Step 3: Cross multiply
   233.21x = 321.83 × 128.31
4. Step 4: Simplify right side
   233.21x = 41,293.69
5. Step 5: Solve for x
   x = 41,293.69/233.21
6. Step 6: Final answer
   x = 177.06