Finding the Fourth Proportional to 142.23, 196.20 and 86.98

Step by Step Solution

1. Step 1: Write the proportion equation
   142.23 : 196.20 = 86.98 : x
2. Step 2: Convert to fraction form
   142.23/196.20 = 86.98/x
3. Step 3: Cross multiply
   142.23x = 196.20 × 86.98
4. Step 4: Simplify right side
   142.23x = 17,065.48
5. Step 5: Solve for x
   x = 17,065.48/142.23
6. Step 6: Final answer
   x = 119.99