Finding the Fourth Proportional to 2,026.88, 3,039.87 and 639.98

Step by Step Solution

1. Step 1: Write the proportion equation
   2,026.88 : 3,039.87 = 639.98 : x
2. Step 2: Convert to fraction form
   2,026.88/3,039.87 = 639.98/x
3. Step 3: Cross multiply
   2,026.88x = 3,039.87 × 639.98
4. Step 4: Simplify right side
   2,026.88x = 1,945,456.00
5. Step 5: Solve for x
   x = 1,945,456.00/2,026.88
6. Step 6: Final answer
   x = 959.83