Finding the Fourth Proportional to 5,105.80, 7,647.90 and 5,105.80

Step by Step Solution

1. Step 1: Write the proportion equation
   5,105.80 : 7,647.90 = 5,105.80 : x
2. Step 2: Convert to fraction form
   5,105.80/7,647.90 = 5,105.80/x
3. Step 3: Cross multiply
   5,105.80x = 7,647.90 × 5,105.80
4. Step 4: Simplify right side
   5,105.80x = 39,048,647.82
5. Step 5: Solve for x
   x = 39,048,647.82/5,105.80
6. Step 6: Final answer
   x = 7,647.90