Finding the Fourth Proportional to 131.10, 196.56 and 90.42

Step by Step Solution

1. Step 1: Write the proportion equation
   131.10 : 196.56 = 90.42 : x
2. Step 2: Convert to fraction form
   131.10/196.56 = 90.42/x
3. Step 3: Cross multiply
   131.10x = 196.56 × 90.42
4. Step 4: Simplify right side
   131.10x = 17,772.96
5. Step 5: Solve for x
   x = 17,772.96/131.10
6. Step 6: Final answer
   x = 135.57