Finding the Fourth Proportional to 3,984.39, 5,978.99 and 1,389.15

Step by Step Solution

1. Step 1: Write the proportion equation
   3,984.39 : 5,978.99 = 1,389.15 : x
2. Step 2: Convert to fraction form
   3,984.39/5,978.99 = 1,389.15/x
3. Step 3: Cross multiply
   3,984.39x = 5,978.99 × 1,389.15
4. Step 4: Simplify right side
   3,984.39x = 8,305,707.01
5. Step 5: Solve for x
   x = 8,305,707.01/3,984.39
6. Step 6: Final answer
   x = 2,084.56