Finding the Fourth Proportional to 142.42, 213.72 and 61.28

Step by Step Solution

1. Step 1: Write the proportion equation
   142.42 : 213.72 = 61.28 : x
2. Step 2: Convert to fraction form
   142.42/213.72 = 61.28/x
3. Step 3: Cross multiply
   142.42x = 213.72 × 61.28
4. Step 4: Simplify right side
   142.42x = 13,096.76
5. Step 5: Solve for x
   x = 13,096.76/142.42
6. Step 6: Final answer
   x = 91.96