Finding the Fourth Proportional to 2,107.89, 3,161.91 and 721.35

Step by Step Solution

1. Step 1: Write the proportion equation
   2,107.89 : 3,161.91 = 721.35 : x
2. Step 2: Convert to fraction form
   2,107.89/3,161.91 = 721.35/x
3. Step 3: Cross multiply
   2,107.89x = 3,161.91 × 721.35
4. Step 4: Simplify right side
   2,107.89x = 2,280,843.78
5. Step 5: Solve for x
   x = 2,280,843.78/2,107.89
6. Step 6: Final answer
   x = 1,082.05