Finding the Fourth Proportional to 89.61, 122.82 and 88.39

Step by Step Solution

1. Step 1: Write the proportion equation
   89.61 : 122.82 = 88.39 : x
2. Step 2: Convert to fraction form
   89.61/122.82 = 88.39/x
3. Step 3: Cross multiply
   89.61x = 122.82 × 88.39
4. Step 4: Simplify right side
   89.61x = 10,855.88
5. Step 5: Solve for x
   x = 10,855.88/89.61
6. Step 6: Final answer
   x = 121.15