Finding the Fourth Proportional to 142.15, 196.06 and 100.71

Step by Step Solution

1. Step 1: Write the proportion equation
   142.15 : 196.06 = 100.71 : x
2. Step 2: Convert to fraction form
   142.15/196.06 = 100.71/x
3. Step 3: Cross multiply
   142.15x = 196.06 × 100.71
4. Step 4: Simplify right side
   142.15x = 19,745.20
5. Step 5: Solve for x
   x = 19,745.20/142.15
6. Step 6: Final answer
   x = 138.90