Finding the Fourth Proportional to 11,815.72, 17,719.17 and 3,916.78

Step by Step Solution

1. Step 1: Write the proportion equation
   11,815.72 : 17,719.17 = 3,916.78 : x
2. Step 2: Convert to fraction form
   11,815.72/17,719.17 = 3,916.78/x
3. Step 3: Cross multiply
   11,815.72x = 17,719.17 × 3,916.78
4. Step 4: Simplify right side
   11,815.72x = 69,402,090.67
5. Step 5: Solve for x
   x = 69,402,090.67/11,815.72
6. Step 6: Final answer
   x = 5,873.71