Finding the Fourth Proportional to 131.89, 181.49 and 128.31

Step by Step Solution

1. Step 1: Write the proportion equation
   131.89 : 181.49 = 128.31 : x
2. Step 2: Convert to fraction form
   131.89/181.49 = 128.31/x
3. Step 3: Cross multiply
   131.89x = 181.49 × 128.31
4. Step 4: Simplify right side
   131.89x = 23,286.34
5. Step 5: Solve for x
   x = 23,286.34/131.89
6. Step 6: Final answer
   x = 176.56