Finding the Fourth Proportional to 142.08, 196.06 and 86.80

Step by Step Solution

1. Step 1: Write the proportion equation
   142.08 : 196.06 = 86.80 : x
2. Step 2: Convert to fraction form
   142.08/196.06 = 86.80/x
3. Step 3: Cross multiply
   142.08x = 196.06 × 86.80
4. Step 4: Simplify right side
   142.08x = 17,018.01
5. Step 5: Solve for x
   x = 17,018.01/142.08
6. Step 6: Final answer
   x = 119.78