Finding the Fourth Proportional to 5,175.55, 7,769.40 and 5,139.10

Step by Step Solution

1. Step 1: Write the proportion equation
   5,175.55 : 7,769.40 = 5,139.10 : x
2. Step 2: Convert to fraction form
   5,175.55/7,769.40 = 5,139.10/x
3. Step 3: Cross multiply
   5,175.55x = 7,769.40 × 5,139.10
4. Step 4: Simplify right side
   5,175.55x = 39,927,723.54
5. Step 5: Solve for x
   x = 39,927,723.54/5,175.55
6. Step 6: Final answer
   x = 7,714.68