Finding the Fourth Proportional to 13,283.05, 19,919.89 and 3,920.57

Step by Step Solution

1. Step 1: Write the proportion equation
   13,283.05 : 19,919.89 = 3,920.57 : x
2. Step 2: Convert to fraction form
   13,283.05/19,919.89 = 3,920.57/x
3. Step 3: Cross multiply
   13,283.05x = 19,919.89 × 3,920.57
4. Step 4: Simplify right side
   13,283.05x = 78,097,265.59
5. Step 5: Solve for x
   x = 78,097,265.59/13,283.05
6. Step 6: Final answer
   x = 5,879.47