Finding the Fourth Proportional to 2,101.52, 3,152.42 and 640.69

Step by Step Solution

1. Step 1: Write the proportion equation
   2,101.52 : 3,152.42 = 640.69 : x
2. Step 2: Convert to fraction form
   2,101.52/3,152.42 = 640.69/x
3. Step 3: Cross multiply
   2,101.52x = 3,152.42 × 640.69
4. Step 4: Simplify right side
   2,101.52x = 2,019,723.97
5. Step 5: Solve for x
   x = 2,019,723.97/2,101.52
6. Step 6: Final answer
   x = 961.08