Finding the Fourth Proportional to 142.05, 196.04 and 86.78

Step by Step Solution

1. Step 1: Write the proportion equation
   142.05 : 196.04 = 86.78 : x
2. Step 2: Convert to fraction form
   142.05/196.04 = 86.78/x
3. Step 3: Cross multiply
   142.05x = 196.04 × 86.78
4. Step 4: Simplify right side
   142.05x = 17,010.94
5. Step 5: Solve for x
   x = 17,010.94/142.05
6. Step 6: Final answer
   x = 119.75