Finding the Fourth Proportional to 2,639.57, 3,643.21 and 1,521.15

Step by Step Solution

1. Step 1: Write the proportion equation
   2,639.57 : 3,643.21 = 1,521.15 : x
2. Step 2: Convert to fraction form
   2,639.57/3,643.21 = 1,521.15/x
3. Step 3: Cross multiply
   2,639.57x = 3,643.21 × 1,521.15
4. Step 4: Simplify right side
   2,639.57x = 5,541,868.89
5. Step 5: Solve for x
   x = 5,541,868.89/2,639.57
6. Step 6: Final answer
   x = 2,099.53