Finding the Fourth Proportional to 2,640.31, 3,960.42 and 1,079.98

Step by Step Solution

1. Step 1: Write the proportion equation
   2,640.31 : 3,960.42 = 1,079.98 : x
2. Step 2: Convert to fraction form
   2,640.31/3,960.42 = 1,079.98/x
3. Step 3: Cross multiply
   2,640.31x = 3,960.42 × 1,079.98
4. Step 4: Simplify right side
   2,640.31x = 4,277,174.39
5. Step 5: Solve for x
   x = 4,277,174.39/2,640.31
6. Step 6: Final answer
   x = 1,619.95