Finding the Fourth Proportional to 2,104.24, 3,156.38 and 643.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,104.24 : 3,156.38 = 643.40 : x
2. Step 2: Convert to fraction form
   2,104.24/3,156.38 = 643.40/x
3. Step 3: Cross multiply
   2,104.24x = 3,156.38 × 643.40
4. Step 4: Simplify right side
   2,104.24x = 2,030,814.89
5. Step 5: Solve for x
   x = 2,030,814.89/2,104.24
6. Step 6: Final answer
   x = 965.11