Finding the Fourth Proportional to 1,399.35, 1,931.46 and 839.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.35 : 1,931.46 = 839.96 : x
2. Step 2: Convert to fraction form
   1,399.35/1,931.46 = 839.96/x
3. Step 3: Cross multiply
   1,399.35x = 1,931.46 × 839.96
4. Step 4: Simplify right side
   1,399.35x = 1,622,349.14
5. Step 5: Solve for x
   x = 1,622,349.14/1,399.35
6. Step 6: Final answer
   x = 1,159.36