Finding the Fourth Proportional to 131.12, 196.61 and 90.56

Step by Step Solution

1. Step 1: Write the proportion equation
   131.12 : 196.61 = 90.56 : x
2. Step 2: Convert to fraction form
   131.12/196.61 = 90.56/x
3. Step 3: Cross multiply
   131.12x = 196.61 × 90.56
4. Step 4: Simplify right side
   131.12x = 17,804.55
5. Step 5: Solve for x
   x = 17,804.55/131.12
6. Step 6: Final answer
   x = 135.79