Finding the Fourth Proportional to 11,318.02, 16,978.17 and 3,920.78

Step by Step Solution

1. Step 1: Write the proportion equation
   11,318.02 : 16,978.17 = 3,920.78 : x
2. Step 2: Convert to fraction form
   11,318.02/16,978.17 = 3,920.78/x
3. Step 3: Cross multiply
   11,318.02x = 16,978.17 × 3,920.78
4. Step 4: Simplify right side
   11,318.02x = 66,567,669.37
5. Step 5: Solve for x
   x = 66,567,669.37/11,318.02
6. Step 6: Final answer
   x = 5,881.56