Finding the Fourth Proportional to 5,173.50, 7,138.71 and 3,078.78

Step by Step Solution

1. Step 1: Write the proportion equation
   5,173.50 : 7,138.71 = 3,078.78 : x
2. Step 2: Convert to fraction form
   5,173.50/7,138.71 = 3,078.78/x
3. Step 3: Cross multiply
   5,173.50x = 7,138.71 × 3,078.78
4. Step 4: Simplify right side
   5,173.50x = 21,978,517.57
5. Step 5: Solve for x
   x = 21,978,517.57/5,173.50
6. Step 6: Final answer
   x = 4,248.29