Finding the Fourth Proportional to 2,643.57, 3,965.27 and 1,257.57

Step by Step Solution

1. Step 1: Write the proportion equation
   2,643.57 : 3,965.27 = 1,257.57 : x
2. Step 2: Convert to fraction form
   2,643.57/3,965.27 = 1,257.57/x
3. Step 3: Cross multiply
   2,643.57x = 3,965.27 × 1,257.57
4. Step 4: Simplify right side
   2,643.57x = 4,986,598.31
5. Step 5: Solve for x
   x = 4,986,598.31/2,643.57
6. Step 6: Final answer
   x = 1,886.31