Finding the Fourth Proportional to 142.71, 196.95 and 90.30

Step by Step Solution

1. Step 1: Write the proportion equation
   142.71 : 196.95 = 90.30 : x
2. Step 2: Convert to fraction form
   142.71/196.95 = 90.30/x
3. Step 3: Cross multiply
   142.71x = 196.95 × 90.30
4. Step 4: Simplify right side
   142.71x = 17,784.59
5. Step 5: Solve for x
   x = 17,784.59/142.71
6. Step 6: Final answer
   x = 124.62