Finding the Fourth Proportional to 1,399.24, 1,930.85 and 839.43

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.24 : 1,930.85 = 839.43 : x
2. Step 2: Convert to fraction form
   1,399.24/1,930.85 = 839.43/x
3. Step 3: Cross multiply
   1,399.24x = 1,930.85 × 839.43
4. Step 4: Simplify right side
   1,399.24x = 1,620,813.42
5. Step 5: Solve for x
   x = 1,620,813.42/1,399.24
6. Step 6: Final answer
   x = 1,158.35