Finding the Fourth Proportional to 5,173.42, 7,139.28 and 2,815.57

Step by Step Solution

1. Step 1: Write the proportion equation
   5,173.42 : 7,139.28 = 2,815.57 : x
2. Step 2: Convert to fraction form
   5,173.42/7,139.28 = 2,815.57/x
3. Step 3: Cross multiply
   5,173.42x = 7,139.28 × 2,815.57
4. Step 4: Simplify right side
   5,173.42x = 20,101,142.59
5. Step 5: Solve for x
   x = 20,101,142.59/5,173.42
6. Step 6: Final answer
   x = 3,885.47