Finding the Fourth Proportional to 2,072.56, 3,107.68 and 839.30

Step by Step Solution

1. Step 1: Write the proportion equation
   2,072.56 : 3,107.68 = 839.30 : x
2. Step 2: Convert to fraction form
   2,072.56/3,107.68 = 839.30/x
3. Step 3: Cross multiply
   2,072.56x = 3,107.68 × 839.30
4. Step 4: Simplify right side
   2,072.56x = 2,608,275.82
5. Step 5: Solve for x
   x = 2,608,275.82/2,072.56
6. Step 6: Final answer
   x = 1,258.48