Finding the Fourth Proportional to 142.25, 196.34 and 86.99

Step by Step Solution

1. Step 1: Write the proportion equation
   142.25 : 196.34 = 86.99 : x
2. Step 2: Convert to fraction form
   142.25/196.34 = 86.99/x
3. Step 3: Cross multiply
   142.25x = 196.34 × 86.99
4. Step 4: Simplify right side
   142.25x = 17,078.20
5. Step 5: Solve for x
   x = 17,078.20/142.25
6. Step 6: Final answer
   x = 120.06