Finding the Fourth Proportional to 2,571.98, 3,858.60 and 840.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,571.98 : 3,858.60 = 840.56 : x
2. Step 2: Convert to fraction form
   2,571.98/3,858.60 = 840.56/x
3. Step 3: Cross multiply
   2,571.98x = 3,858.60 × 840.56
4. Step 4: Simplify right side
   2,571.98x = 3,243,384.82
5. Step 5: Solve for x
   x = 3,243,384.82/2,571.98
6. Step 6: Final answer
   x = 1,261.05