Finding the Fourth Proportional to 2,103.69, 3,156.03 and 642.81

Step by Step Solution

1. Step 1: Write the proportion equation
   2,103.69 : 3,156.03 = 642.81 : x
2. Step 2: Convert to fraction form
   2,103.69/3,156.03 = 642.81/x
3. Step 3: Cross multiply
   2,103.69x = 3,156.03 × 642.81
4. Step 4: Simplify right side
   2,103.69x = 2,028,727.64
5. Step 5: Solve for x
   x = 2,028,727.64/2,103.69
6. Step 6: Final answer
   x = 964.37