Finding the Fourth Proportional to 89.07, 122.25 and 85.31

Step by Step Solution

1. Step 1: Write the proportion equation
   89.07 : 122.25 = 85.31 : x
2. Step 2: Convert to fraction form
   89.07/122.25 = 85.31/x
3. Step 3: Cross multiply
   89.07x = 122.25 × 85.31
4. Step 4: Simplify right side
   89.07x = 10,429.15
5. Step 5: Solve for x
   x = 10,429.15/89.07
6. Step 6: Final answer
   x = 117.09