Finding the Fourth Proportional to 3,978.98, 5,969.38 and 2,131.89

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.98 : 5,969.38 = 2,131.89 : x
2. Step 2: Convert to fraction form
   3,978.98/5,969.38 = 2,131.89/x
3. Step 3: Cross multiply
   3,978.98x = 5,969.38 × 2,131.89
4. Step 4: Simplify right side
   3,978.98x = 12,726,031.68
5. Step 5: Solve for x
   x = 12,726,031.68/3,978.98
6. Step 6: Final answer
   x = 3,198.32