Finding the Fourth Proportional to 85.23, 128.52 and 83.61

Step by Step Solution

1. Step 1: Write the proportion equation
   85.23 : 128.52 = 83.61 : x
2. Step 2: Convert to fraction form
   85.23/128.52 = 83.61/x
3. Step 3: Cross multiply
   85.23x = 128.52 × 83.61
4. Step 4: Simplify right side
   85.23x = 10,745.56
5. Step 5: Solve for x
   x = 10,745.56/85.23
6. Step 6: Final answer
   x = 126.08