Finding the Fourth Proportional to 2,103.89, 3,155.72 and 642.93

Step by Step Solution

1. Step 1: Write the proportion equation
   2,103.89 : 3,155.72 = 642.93 : x
2. Step 2: Convert to fraction form
   2,103.89/3,155.72 = 642.93/x
3. Step 3: Cross multiply
   2,103.89x = 3,155.72 × 642.93
4. Step 4: Simplify right side
   2,103.89x = 2,028,908.67
5. Step 5: Solve for x
   x = 2,028,908.67/2,103.89
6. Step 6: Final answer
   x = 964.36