Finding the Fourth Proportional to 3,978.30, 5,969.14 and 2,128.94

Step by Step Solution

1. Step 1: Write the proportion equation
   3,978.30 : 5,969.14 = 2,128.94 : x
2. Step 2: Convert to fraction form
   3,978.30/5,969.14 = 2,128.94/x
3. Step 3: Cross multiply
   3,978.30x = 5,969.14 × 2,128.94
4. Step 4: Simplify right side
   3,978.30x = 12,707,928.65
5. Step 5: Solve for x
   x = 12,707,928.65/3,978.30
6. Step 6: Final answer
   x = 3,194.31