Finding the Fourth Proportional to 8,961.89, 13,375.06 and 8,728.61

Step by Step Solution

1. Step 1: Write the proportion equation
   8,961.89 : 13,375.06 = 8,728.61 : x
2. Step 2: Convert to fraction form
   8,961.89/13,375.06 = 8,728.61/x
3. Step 3: Cross multiply
   8,961.89x = 13,375.06 × 8,728.61
4. Step 4: Simplify right side
   8,961.89x = 116,745,593.77
5. Step 5: Solve for x
   x = 116,745,593.77/8,961.89
6. Step 6: Final answer
   x = 13,026.90