Finding the Fourth Proportional to 2,103.98, 3,155 and 642.82

Step by Step Solution

1. Step 1: Write the proportion equation
   2,103.98 : 3,155 = 642.82 : x
2. Step 2: Convert to fraction form
   2,103.98/3,155 = 642.82/x
3. Step 3: Cross multiply
   2,103.98x = 3,155 × 642.82
4. Step 4: Simplify right side
   2,103.98x = 2,028,097.10
5. Step 5: Solve for x
   x = 2,028,097.10/2,103.98
6. Step 6: Final answer
   x = 963.93