Finding the Fourth Proportional to 1,391.48, 1,919.82 and 839.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.48 : 1,919.82 = 839.48 : x
2. Step 2: Convert to fraction form
   1,391.48/1,919.82 = 839.48/x
3. Step 3: Cross multiply
   1,391.48x = 1,919.82 × 839.48
4. Step 4: Simplify right side
   1,391.48x = 1,611,650.49
5. Step 5: Solve for x
   x = 1,611,650.49/1,391.48
6. Step 6: Final answer
   x = 1,158.23