Finding the Fourth Proportional to 142.61, 196.82 and 90.15

Step by Step Solution

1. Step 1: Write the proportion equation
   142.61 : 196.82 = 90.15 : x
2. Step 2: Convert to fraction form
   142.61/196.82 = 90.15/x
3. Step 3: Cross multiply
   142.61x = 196.82 × 90.15
4. Step 4: Simplify right side
   142.61x = 17,742.87
5. Step 5: Solve for x
   x = 17,742.87/142.61
6. Step 6: Final answer
   x = 124.42