Finding the Fourth Proportional to 142.15, 213.23 and 61.05

Step by Step Solution

1. Step 1: Write the proportion equation
   142.15 : 213.23 = 61.05 : x
2. Step 2: Convert to fraction form
   142.15/213.23 = 61.05/x
3. Step 3: Cross multiply
   142.15x = 213.23 × 61.05
4. Step 4: Simplify right side
   142.15x = 13,017.69
5. Step 5: Solve for x
   x = 13,017.69/142.15
6. Step 6: Final answer
   x = 91.58