Finding the Fourth Proportional to 8,661.57, 12,966.42 and 5,577.09

Step by Step Solution

1. Step 1: Write the proportion equation
   8,661.57 : 12,966.42 = 5,577.09 : x
2. Step 2: Convert to fraction form
   8,661.57/12,966.42 = 5,577.09/x
3. Step 3: Cross multiply
   8,661.57x = 12,966.42 × 5,577.09
4. Step 4: Simplify right side
   8,661.57x = 72,314,891.32
5. Step 5: Solve for x
   x = 72,314,891.32/8,661.57
6. Step 6: Final answer
   x = 8,348.94