Finding the Fourth Proportional to 2,168.20, 3,257.50 and 1,389.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,168.20 : 3,257.50 = 1,389.72 : x
2. Step 2: Convert to fraction form
   2,168.20/3,257.50 = 1,389.72/x
3. Step 3: Cross multiply
   2,168.20x = 3,257.50 × 1,389.72
4. Step 4: Simplify right side
   2,168.20x = 4,527,012.90
5. Step 5: Solve for x
   x = 4,527,012.90/2,168.20
6. Step 6: Final answer
   x = 2,087.91