Finding the Fourth Proportional to 13,510.72, 20,259.60 and 5,715.28

Step by Step Solution

1. Step 1: Write the proportion equation
   13,510.72 : 20,259.60 = 5,715.28 : x
2. Step 2: Convert to fraction form
   13,510.72/20,259.60 = 5,715.28/x
3. Step 3: Cross multiply
   13,510.72x = 20,259.60 × 5,715.28
4. Step 4: Simplify right side
   13,510.72x = 115,789,286.69
5. Step 5: Solve for x
   x = 115,789,286.69/13,510.72
6. Step 6: Final answer
   x = 8,570.18