Finding the Fourth Proportional to 1,399.01, 1,931.06 and 839.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.01 : 1,931.06 = 839.57 : x
2. Step 2: Convert to fraction form
   1,399.01/1,931.06 = 839.57/x
3. Step 3: Cross multiply
   1,399.01x = 1,931.06 × 839.57
4. Step 4: Simplify right side
   1,399.01x = 1,621,260.04
5. Step 5: Solve for x
   x = 1,621,260.04/1,399.01
6. Step 6: Final answer
   x = 1,158.86