Finding the Fourth Proportional to 2,638.40, 3,960.50 and 1,321.79

Step by Step Solution

1. Step 1: Write the proportion equation
   2,638.40 : 3,960.50 = 1,321.79 : x
2. Step 2: Convert to fraction form
   2,638.40/3,960.50 = 1,321.79/x
3. Step 3: Cross multiply
   2,638.40x = 3,960.50 × 1,321.79
4. Step 4: Simplify right side
   2,638.40x = 5,234,956.30
5. Step 5: Solve for x
   x = 5,234,956.30/2,638.40
6. Step 6: Final answer
   x = 1,984.14