Finding the Fourth Proportional to 12,816.78, 17,687.61 and 7,511.28

Step by Step Solution

1. Step 1: Write the proportion equation
   12,816.78 : 17,687.61 = 7,511.28 : x
2. Step 2: Convert to fraction form
   12,816.78/17,687.61 = 7,511.28/x
3. Step 3: Cross multiply
   12,816.78x = 17,687.61 × 7,511.28
4. Step 4: Simplify right side
   12,816.78x = 132,856,591.24
5. Step 5: Solve for x
   x = 132,856,591.24/12,816.78
6. Step 6: Final answer
   x = 10,365.83