Finding the Fourth Proportional to 142.16, 196.20 and 90.56

Step by Step Solution

1. Step 1: Write the proportion equation
   142.16 : 196.20 = 90.56 : x
2. Step 2: Convert to fraction form
   142.16/196.20 = 90.56/x
3. Step 3: Cross multiply
   142.16x = 196.20 × 90.56
4. Step 4: Simplify right side
   142.16x = 17,767.87
5. Step 5: Solve for x
   x = 17,767.87/142.16
6. Step 6: Final answer
   x = 124.99