Finding the Fourth Proportional to 2,571.56, 3,856.38 and 839.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,571.56 : 3,856.38 = 839.72 : x
2. Step 2: Convert to fraction form
   2,571.56/3,856.38 = 839.72/x
3. Step 3: Cross multiply
   2,571.56x = 3,856.38 × 839.72
4. Step 4: Simplify right side
   2,571.56x = 3,238,279.41
5. Step 5: Solve for x
   x = 3,238,279.41/2,571.56
6. Step 6: Final answer
   x = 1,259.27