Finding the Fourth Proportional to 131.31, 196.99 and 91.91

Step by Step Solution

1. Step 1: Write the proportion equation
   131.31 : 196.99 = 91.91 : x
2. Step 2: Convert to fraction form
   131.31/196.99 = 91.91/x
3. Step 3: Cross multiply
   131.31x = 196.99 × 91.91
4. Step 4: Simplify right side
   131.31x = 18,105.35
5. Step 5: Solve for x
   x = 18,105.35/131.31
6. Step 6: Final answer
   x = 137.88