Finding the Fourth Proportional to 2,103.16, 3,155.23 and 642.31

Step by Step Solution

1. Step 1: Write the proportion equation
   2,103.16 : 3,155.23 = 642.31 : x
2. Step 2: Convert to fraction form
   2,103.16/3,155.23 = 642.31/x
3. Step 3: Cross multiply
   2,103.16x = 3,155.23 × 642.31
4. Step 4: Simplify right side
   2,103.16x = 2,026,635.78
5. Step 5: Solve for x
   x = 2,026,635.78/2,103.16
6. Step 6: Final answer
   x = 963.61