Finding the Fourth Proportional to 142.05, 196.06 and 86.81

Step by Step Solution

1. Step 1: Write the proportion equation
   142.05 : 196.06 = 86.81 : x
2. Step 2: Convert to fraction form
   142.05/196.06 = 86.81/x
3. Step 3: Cross multiply
   142.05x = 196.06 × 86.81
4. Step 4: Simplify right side
   142.05x = 17,019.97
5. Step 5: Solve for x
   x = 17,019.97/142.05
6. Step 6: Final answer
   x = 119.82