Finding the Fourth Proportional to 89.05, 122.72 and 86.77

Step by Step Solution

1. Step 1: Write the proportion equation
   89.05 : 122.72 = 86.77 : x
2. Step 2: Convert to fraction form
   89.05/122.72 = 86.77/x
3. Step 3: Cross multiply
   89.05x = 122.72 × 86.77
4. Step 4: Simplify right side
   89.05x = 10,648.13
5. Step 5: Solve for x
   x = 10,648.13/89.05
6. Step 6: Final answer
   x = 119.58