Finding the Fourth Proportional to 5,172.96, 7,138.72 and 2,815.08

Step by Step Solution

1. Step 1: Write the proportion equation
   5,172.96 : 7,138.72 = 2,815.08 : x
2. Step 2: Convert to fraction form
   5,172.96/7,138.72 = 2,815.08/x
3. Step 3: Cross multiply
   5,172.96x = 7,138.72 × 2,815.08
4. Step 4: Simplify right side
   5,172.96x = 20,096,067.90
5. Step 5: Solve for x
   x = 20,096,067.90/5,172.96
6. Step 6: Final answer
   x = 3,884.83