Finding the Fourth Proportional to 3,886.21, 5,359.35 and 2,557.61

Step by Step Solution

1. Step 1: Write the proportion equation
   3,886.21 : 5,359.35 = 2,557.61 : x
2. Step 2: Convert to fraction form
   3,886.21/5,359.35 = 2,557.61/x
3. Step 3: Cross multiply
   3,886.21x = 5,359.35 × 2,557.61
4. Step 4: Simplify right side
   3,886.21x = 13,707,127.15
5. Step 5: Solve for x
   x = 13,707,127.15/3,886.21
6. Step 6: Final answer
   x = 3,527.12