Finding the Fourth Proportional to 2,399.61, 3,599.57 and 839.55

Step by Step Solution

1. Step 1: Write the proportion equation
   2,399.61 : 3,599.57 = 839.55 : x
2. Step 2: Convert to fraction form
   2,399.61/3,599.57 = 839.55/x
3. Step 3: Cross multiply
   2,399.61x = 3,599.57 × 839.55
4. Step 4: Simplify right side
   2,399.61x = 3,022,014.80
5. Step 5: Solve for x
   x = 3,022,014.80/2,399.61
6. Step 6: Final answer
   x = 1,259.38