Finding the Fourth Proportional to 11,208.78, 16,815.72 and 3,418.20

Step by Step Solution

1. Step 1: Write the proportion equation
   11,208.78 : 16,815.72 = 3,418.20 : x
2. Step 2: Convert to fraction form
   11,208.78/16,815.72 = 3,418.20/x
3. Step 3: Cross multiply
   11,208.78x = 16,815.72 × 3,418.20
4. Step 4: Simplify right side
   11,208.78x = 57,479,494.10
5. Step 5: Solve for x
   x = 57,479,494.10/11,208.78
6. Step 6: Final answer
   x = 5,128.08