Finding the Fourth Proportional to 217.37, 300.00 and 128.89

Step by Step Solution

1. Step 1: Write the proportion equation
   217.37 : 300.00 = 128.89 : x
2. Step 2: Convert to fraction form
   217.37/300.00 = 128.89/x
3. Step 3: Cross multiply
   217.37x = 300.00 × 128.89
4. Step 4: Simplify right side
   217.37x = 38,664.86
5. Step 5: Solve for x
   x = 38,664.86/217.37
6. Step 6: Final answer
   x = 177.88