Finding the Fourth Proportional to 131.23, 196.59 and 90.49

Step by Step Solution

1. Step 1: Write the proportion equation
   131.23 : 196.59 = 90.49 : x
2. Step 2: Convert to fraction form
   131.23/196.59 = 90.49/x
3. Step 3: Cross multiply
   131.23x = 196.59 × 90.49
4. Step 4: Simplify right side
   131.23x = 17,789.43
5. Step 5: Solve for x
   x = 17,789.43/131.23
6. Step 6: Final answer
   x = 135.56