Finding the Fourth Proportional to 142.72, 196.96 and 83.72

Step by Step Solution

1. Step 1: Write the proportion equation
   142.72 : 196.96 = 83.72 : x
2. Step 2: Convert to fraction form
   142.72/196.96 = 83.72/x
3. Step 3: Cross multiply
   142.72x = 196.96 × 83.72
4. Step 4: Simplify right side
   142.72x = 16,489.77
5. Step 5: Solve for x
   x = 16,489.77/142.72
6. Step 6: Final answer
   x = 115.54