Finding the Fourth Proportional to 5,165.59, 7,128.49 and 2,807.72

Step by Step Solution

1. Step 1: Write the proportion equation
   5,165.59 : 7,128.49 = 2,807.72 : x
2. Step 2: Convert to fraction form
   5,165.59/7,128.49 = 2,807.72/x
3. Step 3: Cross multiply
   5,165.59x = 7,128.49 × 2,807.72
4. Step 4: Simplify right side
   5,165.59x = 20,014,789.90
5. Step 5: Solve for x
   x = 20,014,789.90/5,165.59
6. Step 6: Final answer
   x = 3,874.64