Finding the Fourth Proportional to 7,815.93, 10,786.49 and 5,128.75

Step by Step Solution

1. Step 1: Write the proportion equation
   7,815.93 : 10,786.49 = 5,128.75 : x
2. Step 2: Convert to fraction form
   7,815.93/10,786.49 = 5,128.75/x
3. Step 3: Cross multiply
   7,815.93x = 10,786.49 × 5,128.75
4. Step 4: Simplify right side
   7,815.93x = 55,321,210.59
5. Step 5: Solve for x
   x = 55,321,210.59/7,815.93
6. Step 6: Final answer
   x = 7,078.01