Finding the Fourth Proportional to 89.50, 134.71 and 81.11

Step by Step Solution

1. Step 1: Write the proportion equation
   89.50 : 134.71 = 81.11 : x
2. Step 2: Convert to fraction form
   89.50/134.71 = 81.11/x
3. Step 3: Cross multiply
   89.50x = 134.71 × 81.11
4. Step 4: Simplify right side
   89.50x = 10,926.33
5. Step 5: Solve for x
   x = 10,926.33/89.50
6. Step 6: Final answer
   x = 122.09