Finding the Fourth Proportional to 2,103.54, 3,155.10 and 642.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,103.54 : 3,155.10 = 642.72 : x
2. Step 2: Convert to fraction form
   2,103.54/3,155.10 = 642.72/x
3. Step 3: Cross multiply
   2,103.54x = 3,155.10 × 642.72
4. Step 4: Simplify right side
   2,103.54x = 2,027,845.87
5. Step 5: Solve for x
   x = 2,027,845.87/2,103.54
6. Step 6: Final answer
   x = 964.02