Finding the Fourth Proportional to 8,665.81, 12,995.80 and 2,821.05

Step by Step Solution

1. Step 1: Write the proportion equation
   8,665.81 : 12,995.80 = 2,821.05 : x
2. Step 2: Convert to fraction form
   8,665.81/12,995.80 = 2,821.05/x
3. Step 3: Cross multiply
   8,665.81x = 12,995.80 × 2,821.05
4. Step 4: Simplify right side
   8,665.81x = 36,661,801.59
5. Step 5: Solve for x
   x = 36,661,801.59/8,665.81
6. Step 6: Final answer
   x = 4,230.63