Finding the Fourth Proportional to 3,940.61, 5,438.15 and 2,172.33

Step by Step Solution

1. Step 1: Write the proportion equation
   3,940.61 : 5,438.15 = 2,172.33 : x
2. Step 2: Convert to fraction form
   3,940.61/5,438.15 = 2,172.33/x
3. Step 3: Cross multiply
   3,940.61x = 5,438.15 × 2,172.33
4. Step 4: Simplify right side
   3,940.61x = 11,813,456.39
5. Step 5: Solve for x
   x = 11,813,456.39/3,940.61
6. Step 6: Final answer
   x = 2,997.88