Finding the Fourth Proportional to 11,920.49, 17,879.89 and 3,155.21

Step by Step Solution

1. Step 1: Write the proportion equation
   11,920.49 : 17,879.89 = 3,155.21 : x
2. Step 2: Convert to fraction form
   11,920.49/17,879.89 = 3,155.21/x
3. Step 3: Cross multiply
   11,920.49x = 17,879.89 × 3,155.21
4. Step 4: Simplify right side
   11,920.49x = 56,414,807.73
5. Step 5: Solve for x
   x = 56,414,807.73/11,920.49
6. Step 6: Final answer
   x = 4,732.59