Finding the Fourth Proportional to 11,815.57, 17,724.37 and 3,916.40

Step by Step Solution

1. Step 1: Write the proportion equation
   11,815.57 : 17,724.37 = 3,916.40 : x
2. Step 2: Convert to fraction form
   11,815.57/17,724.37 = 3,916.40/x
3. Step 3: Cross multiply
   11,815.57x = 17,724.37 × 3,916.40
4. Step 4: Simplify right side
   11,815.57x = 69,415,731.30
5. Step 5: Solve for x
   x = 69,415,731.30/11,815.57
6. Step 6: Final answer
   x = 5,874.94