Finding the Fourth Proportional to 8,870.28, 13,257.30 and 8,169.72

Step by Step Solution

1. Step 1: Write the proportion equation
   8,870.28 : 13,257.30 = 8,169.72 : x
2. Step 2: Convert to fraction form
   8,870.28/13,257.30 = 8,169.72/x
3. Step 3: Cross multiply
   8,870.28x = 13,257.30 × 8,169.72
4. Step 4: Simplify right side
   8,870.28x = 108,308,428.96
5. Step 5: Solve for x
   x = 108,308,428.96/8,870.28
6. Step 6: Final answer
   x = 12,210.26