Finding the Fourth Proportional to 3,978.38, 5,969.20 and 2,131.58

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.38 : 5,969.20 = 2,131.58 : x
2. Step 2: Convert to fraction form
   3,978.38/5,969.20 = 2,131.58/x
3. Step 3: Cross multiply
   3,978.38x = 5,969.20 × 2,131.58
4. Step 4: Simplify right side
   3,978.38x = 12,723,827.34
5. Step 5: Solve for x
   x = 12,723,827.34/3,978.38
6. Step 6: Final answer
   x = 3,198.24