Finding the Fourth Proportional to 90.21, 134.56 and 80.49

Step by Step Solution

1. Step 1: Write the proportion equation
   90.21 : 134.56 = 80.49 : x
2. Step 2: Convert to fraction form
   90.21/134.56 = 80.49/x
3. Step 3: Cross multiply
   90.21x = 134.56 × 80.49
4. Step 4: Simplify right side
   90.21x = 10,831.34
5. Step 5: Solve for x
   x = 10,831.34/90.21
6. Step 6: Final answer
   x = 120.06