Finding the Fourth Proportional to 2,025.50, 3,038.65 and 639.05

Step by Step Solution

1. Step 1: Write the proportion equation
   2,025.50 : 3,038.65 = 639.05 : x
2. Step 2: Convert to fraction form
   2,025.50/3,038.65 = 639.05/x
3. Step 3: Cross multiply
   2,025.50x = 3,038.65 × 639.05
4. Step 4: Simplify right side
   2,025.50x = 1,941,834.09
5. Step 5: Solve for x
   x = 1,941,834.09/2,025.50
6. Step 6: Final answer
   x = 958.70