Finding the Fourth Proportional to 2,689.42, 4,025.45 and 1,389.10

Step by Step Solution

1. Step 1: Write the proportion equation
   2,689.42 : 4,025.45 = 1,389.10 : x
2. Step 2: Convert to fraction form
   2,689.42/4,025.45 = 1,389.10/x
3. Step 3: Cross multiply
   2,689.42x = 4,025.45 × 1,389.10
4. Step 4: Simplify right side
   2,689.42x = 5,591,752.60
5. Step 5: Solve for x
   x = 5,591,752.60/2,689.42
6. Step 6: Final answer
   x = 2,079.17