Finding the Fourth Proportional to 2,131.55, 3,198.11 and 961.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,131.55 : 3,198.11 = 961.20 : x
2. Step 2: Convert to fraction form
   2,131.55/3,198.11 = 961.20/x
3. Step 3: Cross multiply
   2,131.55x = 3,198.11 × 961.20
4. Step 4: Simplify right side
   2,131.55x = 3,074,023.33
5. Step 5: Solve for x
   x = 3,074,023.33/2,131.55
6. Step 6: Final answer
   x = 1,442.15