Finding the Fourth Proportional to 1,398.45, 1,930.02 and 839.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.45 : 1,930.02 = 839.10 : x
2. Step 2: Convert to fraction form
   1,398.45/1,930.02 = 839.10/x
3. Step 3: Cross multiply
   1,398.45x = 1,930.02 × 839.10
4. Step 4: Simplify right side
   1,398.45x = 1,619,479.78
5. Step 5: Solve for x
   x = 1,619,479.78/1,398.45
6. Step 6: Final answer
   x = 1,158.05