Finding the Fourth Proportional to 2,078.10, 2,857.41 and 1,991.70

Step by Step Solution

1. Step 1: Write the proportion equation
   2,078.10 : 2,857.41 = 1,991.70 : x
2. Step 2: Convert to fraction form
   2,078.10/2,857.41 = 1,991.70/x
3. Step 3: Cross multiply
   2,078.10x = 2,857.41 × 1,991.70
4. Step 4: Simplify right side
   2,078.10x = 5,691,103.50
5. Step 5: Solve for x
   x = 5,691,103.50/2,078.10
6. Step 6: Final answer
   x = 2,738.61