Finding the Fourth Proportional to 11,385.83, 17,078.72 and 3,990.28

Step by Step Solution

1. Step 1: Write the proportion equation
   11,385.83 : 17,078.72 = 3,990.28 : x
2. Step 2: Convert to fraction form
   11,385.83/17,078.72 = 3,990.28/x
3. Step 3: Cross multiply
   11,385.83x = 17,078.72 × 3,990.28
4. Step 4: Simplify right side
   11,385.83x = 68,148,844.22
5. Step 5: Solve for x
   x = 68,148,844.22/11,385.83
6. Step 6: Final answer
   x = 5,985.41