Finding the Fourth Proportional to 5,105.72, 7,653.12 and 2,639.88

Step by Step Solution

1. Step 1: Write the proportion equation
   5,105.72 : 7,653.12 = 2,639.88 : x
2. Step 2: Convert to fraction form
   5,105.72/7,653.12 = 2,639.88/x
3. Step 3: Cross multiply
   5,105.72x = 7,653.12 × 2,639.88
4. Step 4: Simplify right side
   5,105.72x = 20,203,318.43
5. Step 5: Solve for x
   x = 20,203,318.43/5,105.72
6. Step 6: Final answer
   x = 3,957.00