Finding the Fourth Proportional to 2,104.69, 3,157.53 and 643.81

Step by Step Solution

1. Step 1: Write the proportion equation
   2,104.69 : 3,157.53 = 643.81 : x
2. Step 2: Convert to fraction form
   2,104.69/3,157.53 = 643.81/x
3. Step 3: Cross multiply
   2,104.69x = 3,157.53 × 643.81
4. Step 4: Simplify right side
   2,104.69x = 2,032,849.39
5. Step 5: Solve for x
   x = 2,032,849.39/2,104.69
6. Step 6: Final answer
   x = 965.87