Finding the Fourth Proportional to 5,105.78, 7,047.07 and 3,115.91

Step by Step Solution

1. Step 1: Write the proportion equation
   5,105.78 : 7,047.07 = 3,115.91 : x
2. Step 2: Convert to fraction form
   5,105.78/7,047.07 = 3,115.91/x
3. Step 3: Cross multiply
   5,105.78x = 7,047.07 × 3,115.91
4. Step 4: Simplify right side
   5,105.78x = 21,958,035.88
5. Step 5: Solve for x
   x = 21,958,035.88/5,105.78
6. Step 6: Final answer
   x = 4,300.62