Finding the Fourth Proportional to 5,128.94, 7,078.17 and 2,890.91

Step by Step Solution

1. Step 1: Write the proportion equation
   5,128.94 : 7,078.17 = 2,890.91 : x
2. Step 2: Convert to fraction form
   5,128.94/7,078.17 = 2,890.91/x
3. Step 3: Cross multiply
   5,128.94x = 7,078.17 × 2,890.91
4. Step 4: Simplify right side
   5,128.94x = 20,462,317.04
5. Step 5: Solve for x
   x = 20,462,317.04/5,128.94
6. Step 6: Final answer
   x = 3,989.58