Finding the Fourth Proportional to 131.38, 196.91 and 77.31

Step by Step Solution

1. Step 1: Write the proportion equation
   131.38 : 196.91 = 77.31 : x
2. Step 2: Convert to fraction form
   131.38/196.91 = 77.31/x
3. Step 3: Cross multiply
   131.38x = 196.91 × 77.31
4. Step 4: Simplify right side
   131.38x = 15,222.73
5. Step 5: Solve for x
   x = 15,222.73/131.38
6. Step 6: Final answer
   x = 115.87